U.S. patent application number 14/907159 was filed with the patent office on 2016-12-22 for method and nodes for providing handover management.
The applicant listed for this patent is TELEFONAKTIEBOLAGET LM ERICSSON (PUBL). Invention is credited to Qian CHEN, Daniel NILSSON, Lars-Bertil OLSSON, Stefan ROMMER, Chunbo WANG.
Application Number | 20160373973 14/907159 |
Document ID | / |
Family ID | 56416417 |
Filed Date | 2016-12-22 |
United States Patent
Application |
20160373973 |
Kind Code |
A1 |
ROMMER; Stefan ; et
al. |
December 22, 2016 |
METHOD AND NODES FOR PROVIDING HANDOVER MANAGEMENT
Abstract
The embodiments herein relate to a method in a Gn/Gp SGSN (111)
for providing handover management. The Gn/Gp SGSN (111) provides a
handover for a UE (101) to and from a non-3GPP and 3GPP by
utilizing a PDP context that was previously created for the UE
(101) during an attach procedure. The previously created PDP
context is for a previously serving PGW (119).
Inventors: |
ROMMER; Stefan; (Vastra
Frolunda, SE) ; CHEN; Qian; (MOLNDAL, SE) ;
NILSSON; Daniel; (ALVlANGEN, SE) ; OLSSON;
Lars-Bertil; (ANGERED, SE) ; WANG; Chunbo;
(SHANHAI, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) |
Shocholm |
|
SE |
|
|
Family ID: |
56416417 |
Appl. No.: |
14/907159 |
Filed: |
January 13, 2016 |
PCT Filed: |
January 13, 2016 |
PCT NO: |
PCT/CN2016/070795 |
371 Date: |
January 22, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62105092 |
Jan 19, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 36/0022 20130101;
H04W 8/04 20130101; H04W 36/14 20130101; H04W 36/0033 20130101 |
International
Class: |
H04W 36/00 20060101
H04W036/00 |
Claims
1. A method in a Gn/Gp Serving General Packet Radio Service Support
Node, SGSN, for providing handover management, the method
comprising: providing a handover for a User Equipment, UE, to and
from non-Third Generation Partnership Project, non-3GPP, and 3GPP
by utilizing a Packet Data Protocol, PDP, context that was
previously created for the UE during an attach procedure, the
previously created PDP context being for a previously serving
Packet data network Gateway, PGW.
2. The method of claim 1, further comprising: transmitting an
identification of the PGW to a Home Location Register, HLR, at a
Packet Data Network, PDN, connection establishment.
3. The method of claim 2, further comprising: receiving an
acknowledgement of the transmitted identification of the PGW from
the HLR.
4. The method of claim 1, further comprising: receiving, from the
PGW, a Delete PDP Context Request message, said Delete PDP Context
Request message comprising an indication that a radio access type
of the UE has changed from 3GPP to non-3GPP.
5. The method of claim 4, wherein the receiving, from the PGW, of
the Delete PDP Context Request message is repeated for several PDP
contexts which corresponds to a Packet Data Network, PDN,
connection handed over to non-3GPP.
6. The method of claim 1, further comprising: receiving, from the
UE, a PDP Context Activation Request message, the PDP Context
Activation Request message comprising a handover flag setting; and
processing the handover flag setting.
7. The method of claim 1, further comprising: sending, to the PGW,
a Create PDP Context Request message comprising an activated
handover flag setting, wherein the activated handover flag setting
indicates a handover request for the UE, and wherein the handover
is a non-3GPP to 3GPP handover.
8. The method of claim 1, further comprising: receiving at least a
part of a context from the PGW in a Create PDP Context Response
message to accept a handover request for the UE, wherein the
context corresponds to a Packet Data Network, PDN, connection of
the UE which is requested for the handover.
9. The method of claim 1, further comprising: based on a
communication previously received from the PGW, identifying whether
the PGW supports a Gn/Gp based handover.
10. The method of claim 1, further comprising: if the Gn/Gp SGSN
learns that the PGW can support the non-3GPP to 3GPP handover,
sending an Update PDP Context Request message with an activated
handover flag setting to the PGW.
11. The method of claim 1, wherein the Gn/Gp SGSN follows legacy
behavior of PDP Activation if the Gn/Gp SGSN learns that the PGW
cannot support the non-3GPP to 3GPP handover.
12. The method of claim 1, further comprising: receiving, an Update
PDP Context Response message from the PGW.
13. The method of claim 1, further comprising: receiving, from the
UE, a PDP Context Activation request message, the PDP Context
Activation Request message comprising a handover flag setting;
analyzing the handover flag setting; if the handover flag setting
is activated: receiving, from a Home Location Register, HLR, an
identification of the PGW serving the UE; and establishing a
handover procedure for the UE with the identified serving PGW; and
if the handover flag setting is not activated: selecting a PGW to
serve the UE; and sending, to the HLR, an identification of the
selected PGW.
14. The method of claim 1, wherein the identification of the PGW is
at least one of a PGW Fully Qualified Domain Name, FQDN, a PGW
Internet Protocol, IP, address, an Access Point Name, APN, and a
Public Land Mobile Network, PLMN, identification.
15. The method of claim 13, wherein the receiving and establishing
further comprises sending, to the serving PGW, a Create PDP Context
Request message comprising an activated handover flag setting.
16. The method of claim 1, wherein the handover is from one of:
Global System for Mobile Communications, GSM, Enhanced Data Rates
for GSM Evolution, EDGE, Radio Access Network/Universal Terrestrial
Radio Access Network, GERAN/UTRAN, to WiFi; WiFi to GERAN/UTRAN;
and GERAN/UTRAN to Evolved-Universal Terrestrial Access Network,
E-UTRAN, and then to WiFi.
17. A method, in a Home Location Register, HLR, for providing
handover management, the method comprising: receiving, from a Gn/Gp
Serving General Packet Radio Service Support Node, SGSN, an
identification of a Packet Data Network Gateway, PGW, at a Packet
Data Network, PDN, connection establishment; storing the
identification of the PGW; and sending the identification of the
PGW to a Home Subscriber Server, HSS.
18. The method of claim 17, further comprising: sending, to the
Gn/Gp SGSN, the identification of the PGW serving the UE upon an
establishment of a handover procedure.
19. The method of claim 17, further comprising: transmitting an
acknowledgement of the received identification of the PGW to the
Gn/Gp SGSN.
20. The method of claim 17, further comprising: when the UE has
decided to handover from non-3GPP to 3GPP, retrieving the
identification of an already allocated PGW from a Home Subscriber
Server, HSS.
21. The method of claim 17, wherein the identification of the PGW
is at least one of a PGW Fully Qualified Domain Name, FQDN, a PGW
Internet Protocol, IP, address, an Access Point Name, APN, and a
Public Land Mobile Network, PLMN, identification.
22. The method of claim 17, wherein the handover is from one of:
Global System for Mobile Communications, GSM, Enhanced Data Rates
for GSM Evolution, EDGE, Radio Access Network/Universal Terrestrial
Radio Access Network, GERAN/UTRAN, to WiFi; WiFi to GERAN/UTRAN;
and GERAN/UTRAN to Evolved-Universal Terrestrial Access Network,
E-UTRAN, and then to WiFi.
23. A method, in a Packet Data Network Gateway, PGW, for providing
handover management, the method comprising: receiving, from a Gn/Gp
Serving General Packet Radio Service Support Node, SGSN, a Create
Packet Data Protocol, PDP, Context Request message comprising an
activated handover flag setting, wherein the activated handover
flag setting indicates a handover request for a User Equipment, UE,
the handover being a non-3GPP to 3GPP handover.
24. The method of claim 23, further comprising: identifying a
context corresponding to a Packet Data Network, PDN, connection of
the UE which is requested for the handover; and sending at least
part of the context to the Gn/Gp SGSN in a Create PDP Context
Response message to accept the handover request for the UE.
25. The method of claim 23, further comprising: transmitting, to
the Gn/Gp SGSN, a Delete PDP Context Request message, said Delete
PDP Context Request message comprising an indication that a radio
access type of the UE has changed from Third Generation Partnership
Project, 3GPP, to non-3GPP.
26. The method of claim 25, wherein the transmitting, to the Gn/Gp
SGSN, the Delete PDP Context Request message is repeated for
several PDP contexts which corresponds to a PDN connection handed
over to non-3GPP.
27. The method of claim 23, further comprising: if the PGW can
support the non-3GPP to 3GPP handover, receiving an Update PDP
Context Request message with the activated handover flag setting
from the Gn/Gp SGSN; and switching a data path from non-3GPP to
3GPPG upon receipt of the Update PDP Context Request message with
the activated handover flag setting; and transmitting an Update PDP
Context Response message to the Gn/Gp SGSN.
28. The method of claim 23, further comprising: establishing a
handover procedure for the UE with the Gn/Gp SGSN.
29. The method of claim 23, wherein the handover is from one of:
Global System for Mobile Communications, GSM, Enhanced Data Rates
for GSM Evolution, EDGE, Radio Access Network/Universal Terrestrial
Radio Access Network, GERAN/UTRAN, to WiFi; WiFi to GERAN/UTRAN;
and GERAN/UTRAN to Evolved-Universal Terrestrial Access Network,
E-UTRAN, and then to WiFi.
30. A Gn/Gp Serving General Packet Radio Service Support Node,
SGSN, for providing handover management, the Gn/Gp SGSN being
configured to: provide a handover for a User Equipment, UE, to and
from non-Third Generation Partnership Project, non-3GPP, and 3GPP
by utilizing a Packet Data Protocol, PDP, context that was
previously created for the UE during an attach procedure, the
previously created PDP context being for a previously serving
Packet data network Gateway, PGW.
31. The Gn/Gp SGSN of claim 30, being further configured to:
transmit an identification of the PGW to a Home Location Register,
HLR, at a Packet Data Network, PDN, connection establishment.
32. The Gn/Gp SGSN of claim 31, being further configured to:
receive an acknowledgement of the transmitted identification of the
PGW from the HLR.
33. The Gn/Gp SGSN claim 30, being further configured to: receive
from the PGW, a Delete PDP Context Request message, said Delete PDP
Context Request message comprising an indication that a radio
access type of the UE has changed from 3GPP to non-3GPP.
34. The Gn/Gp SGSN of claim 33, being further configured to: repeat
the receiving, from the PGW, of the Delete PDP Context Request
message for several PDP contexts which corresponds to a Packet Data
Network, PDN, connection handed over to non-3GPP.
35. The Gn/Gp SGSN of claim 30, being further configured to:
receive, from the UE, a PDP Context Activation Request message, the
PDP Context Activation Request message comprising a handover flag
setting; and process the handover flag setting.
36. The Gn/Gp SGSN of claim 30, being further configured to: send,
to the PGW, a Create PDP Context Request message comprising an
activated handover flag setting, wherein the activated handover
flag setting indicates a handover request for the UE, and wherein
the handover is a non-3GPP to 3GPP handover.
37. The Gn/Gp SGSN of claim 30, being further configured to:
receive at least a part of a context from the PGW in a Create PDP
Context Response message to accept a handover request for the UE,
wherein the context corresponds to a Packet Data Network, PDN,
connection of the UE which is requested for the handover.
38. The Gn/Gp SGSN of claim 30, being further configured to:
identify, based on a communication previously received from the
PGW, whether the PGW supports a Gn/Gp based handover.
39. The Gn/Gp SGSN of claim 30, being further configured to: send
an Update PDP Context Request message with an activated handover
flag setting to the PGW if the Gn/Gp SGSN learns that the PGW can
support the non-3GPP to 3GPP handover.
40. The Gn/Gp SGSN of claim 30, wherein the Gn/Gp SGSN is
configured to follow legacy behavior of PDP Activation if the Gn/Gp
SGSN learns that the PGW cannot support the non-3GPP to 3GPP
handover.
41. The Gn/Gp SGSN of claim 30, being further configured to:
receive an Update PDP Context Response message from the PGW.
42. The Gn/Gp SGSN of claim 30, being further configured to:
receive, from the UE, a PDP Context Activation Request message, the
PDP Context Activation Request message comprising a handover flag
setting; analyze the handover flag setting; if the handover flag
setting is activated: receive, from a Home Location Register, HLR,
an identification of the PGW serving the UE; and establish a
handover procedure for the UE with the identified serving PGW; and
if the handover flag setting is not activated: select a PGW to
serve the UE; and send, to the HLR, an identification of the
selected PGW.
43. The Gn/Gp SGSN of claim 30, wherein the identification of the
PGW is at least one of a PGW Fully Qualified Domain Name, FQDN, a
PGW Internet Protocol, IP, address, an Access Point Name, APN, and
a Public Land Mobile Network, PLMN, identification.
44. The Gn/Gp SGSN of claim 42, being further configured to: send,
to the serving PGW, a Create PDP Context Request message comprising
an activated handover flag setting.
45. The Gn/Gp SGSN of claim 30, wherein the handover is from one
of: Global System for Mobile Communications, GSM, Enhanced Data
Rates for GSM Evolution, EDGE, Radio Access Network/Universal
Terrestrial Radio Access Network, GERAN/UTRAN, to WiFi; WiFi to
GERAN/UTRAN; and GERAN/UTRAN to Evolved-Universal Terrestrial
Access Network, E-UTRAN, and then to WiFi.
46. A Home Location Register, HLR, for providing handover
management, the HLR being configured to: receive, from a Gn/Gp
Serving General Packet Radio Service Support Node, SGSN, an
identification of a Packet Data Network Gateway, PGW, at a Packet
Data Network, PDN, connection establishment; store the
identification of the PGW; and send the identification of the PGW
to a Home Subscriber Server, HSS.
47. The HLR of claim 46, being further configured to: send, to the
Gn/Gp SGSN, the identification of the PGW serving the UE upon an
establishment of a handover procedure.
48. The HLR of claim 46, being further configured to: transmit an
acknowledgement of the received identification of the PGW to the
Gn/Gp SGSN.
49. The HLR of claim 46, being further configured to: retrieve,
when the UE has decided to handover from non-3GPP to 3GPP, the
identification of an already allocated PGW from a Home Subscriber
Server, HSS.
50. The HLR of claim 46, wherein the identification of the PGW is
at least one of a PGW Fully Qualified Domain Name, FQDN, a PGW
Internet Protocol, IP, address, an Access Point Name, APN, and a
Public Land Mobile Network, PLMN, identification.
51. The HLR of claim 46, wherein the handover is from one of:
Global System for Mobile Communications, GSM, Enhanced Data Rates
for GSM Evolution, EDGE, Radio Access Network/Universal Terrestrial
Radio Access Network, GERAN/UTRAN, to WiFi; WiFi to GERAN/UTRAN;
and GERAN/UTRAN to Evolved-Universal Terrestrial Access Network,
E-UTRAN, and then to WiFi.
52. A Packet Data Network Gateway, PGW, for providing handover
management, the PGW being configured to: receive, from a Gn/Gp
Serving General Packet Radio Service Support Node, SGSN, a Create
Packet Data Protocol, PDP, Context Request message comprising an
activated handover flag setting, the activated handover flag
setting indicating a handover request for a User Equipment, UE, and
the handover being a non-3GPP to 3GPP handover.
53. The PGW of claim 52, being further configured to: identify a
context corresponding to a Packet Data Network, PDN, connection of
the UE which is requested for the handover; and send at least part
of the context to the Gn/Gp SGSN in a Create PDP Context Response
message to accept the handover request for the UE.
54. The PGW of claim 52, being further configured to: transmit, to
the Gn/Gp SGSN, a Delete PDP Context Request message, said Delete
PDP Context Request message comprising an indication that a radio
access type of the UE has changed from Third Generation Partnership
Project, 3GPP, to non-3GPP.
55. The PGW of claim 54, being further configured to: repeat the
transmission, to the Gn/Gp SGSN, of the Delete PDP Context Request
message for several PDP contexts which corresponds to a PDN
connection handed over to non-3GPP.
56. The PGW of claim 52, being further configured to: receive, if
the PGW can support the non-3GPP to 3GPP handover, an Update PDP
Context Request message with the activated handover flag setting
from the Gn/Gp SGSN; switch a data path from non-3GPP to 3GPPG upon
receipt of the Update PDP Context Request message with the
activated handover flag setting; and transmit an Update PDP Context
Response message to the Gn/Gp SGSN.
57. The PGW of claim 52, being further configured to: establish a
handover procedure for the UE with the Gn/Gp SGSN.
58. The PGW of claim 52, wherein the handover is from one of:
Global System for Mobile Communications, GSM, Enhanced Data Rates
for GSM Evolution, EDGE, Radio Access Network/Universal Terrestrial
Radio Access Network, GERAN/UTRAN, to WiFi; WiFi to GERAN/UTRAN;
and GERAN/UTRAN to Evolved-Universal Terrestrial Access Network,
E-UTRAN, and then to WiFi.
59. A computer storage medium storing a computer program comprising
instructions which, when executed on at least one processor, cause
the at least one processor to carry out a method in a Gn/GD Serving
General Packet Radio Service Support Node, SGSN, for providing
handover management, the method comprising: providing a handover
for a User Equipment, UE, to and from non-Third Generation
Partnership Project, non-3GPP, and 3GPP by utilizing a Packet Data
Protocol, PDP, context that was previously created for the UE
during an attach procedure, the previously created PDP context
being for a previously serving Packet data network Gateway,
PGW.
60. (canceled)
61. A computer storage medium storing a computer program comprising
instructions which, when executed on at least one processor, cause
the at least one processor to carry out a method, in a Home
Location Register, HLR, for providing handover management, the
method comprising: receiving, from a Gn/Gp Serving General Packet
Radio Service Support Node, SGSN, an identification of a Packet
Data Network Gateway, PGW, at a Packet Data Network, PDN,
connection establishment, storing the identification of the PGW;
and sending the identification of the PGW to a Home Subscriber
Server, HSS.
62. (canceled)
63. A computer storage medium storing a computer program comprising
instructions which, when executed on at least one processor, cause
the at least one processor to carry out a method, in a Packet Data
Network Gateway, PGW, for providing handover management, the method
comprising: receiving, from a Gn/Gp Serving General Packet Radio
Service Support Node, SGSN, a Create Packet Data Protocol, PDP,
Context Request message comprising an activated handover flag
setting, wherein the activated handover flag setting indicates a
handover request for a User Equipment, UE, the handover being a
non-3GPP to 3GPP handover.
64. (canceled)
Description
TECHNICAL FIELD
[0001] Embodiments herein relate generally to a Gn/Gp Serving
General Packet Radio Service Support Node (SGSN), a method
performed by the Gn/Gp SGSN, a Home Location Register (HLR), a
method performed by the HLR, a Packet Data Network Gateway (PGW)
and a method performed by the PGW. More particularly the
embodiments herein relate to providing HandOver (HO)
management.
BACKGROUND
[0002] In a typical cellular system, also referred to as a wireless
communications network, wireless devices, also known as mobile
stations and/or User Equipment (UE) units communicate via a Radio
Access Network (RAN) to one or more Core Networks (CN). The
wireless devices can be mobile stations or UE units such as mobile
telephones also known as cellular telephones, and laptops with
wireless capability, e.g. mobile termination, and thus can be, for
example, portable, pocket, hand-held, computer-comprised, or
car-mounted mobile devices which communicate voice and/or data with
a radio access network.
[0003] The radio access network covers a geographical area which is
divided into cell areas. Each cell area is served by a base
station, e.g. a Radio Base Station (RBS), which in some networks is
also called NodeB or B node or Evolved NodeB (eNB, eNodeB) and
which in this document also is referred to as a base station. A
cell is a geographical area where radio coverage is provided by the
radio base station equipment at a base station site. Each cell is
identified by an identity (Id, ID) within the local radio area,
which is broadcast in the cell. The base stations communicate over
the air interface operating on radio frequencies with the UE units
within range of the base stations.
[0004] In some versions of the radio access network, several base
stations are typically connected, e.g. by landlines or microwave,
to a Radio Network Controller (RNC). The radio network controller,
also sometimes termed a Base Station Controller (BSC), supervises
and coordinates various activities of the plural base stations
connected thereto. The radio network controllers are typically
connected to one or more core networks (CN).
[0005] The Universal Mobile Telecommunications System (UMTS) is a
Third Generation (3G) mobile communication system, which evolved
from the Global System for Mobile Communications (GSM), and is
intended to provide improved mobile communication services based on
Wideband Code Division Multiple Access (WCDMA) access technology.
UMTS Terrestrial Radio Access Network (UTRAN) is essentially a
radio access network using WCDMA for UE units. The Third Generation
Partnership Project (3GPP) has undertaken to evolve further the
UTRAN and GSM based radio access network technologies. Long Term
Evolution (LTE) together with Evolved Packet Core (EPC) is the
newest addition to the 3GPP family.
GENERAL OVERVIEW
[0006] FIG. 1 provides a general example of a communication network
100. The communication network 100 may also be referred to as a
wireless communications network. As shown in FIG. 1, a wireless
device or user equipment (UE) 101 may be in communication with a
RAN node 102, 103, 104 in a GSM Edge Radio Access Network (GERAN),
or in a UTRAN or an Evolved UTRAN (E-UTRAN) subsystem,
respectively, in order to access a Packet Data Network (PDN) 105
with services and applications of a service provide or operator,
i.e. in order to access communication to an operator or application
server. GERAN may also be referred to as Second Generation (2G),
UTRAN may be referred to as 3G and E-UTRAN may be referred to as
Fourth Generation (4G). In gaining access to the PDN 105 (e.g.
Application Function (AF) or hosts), the UTRAN/E-UTRAN/GERAN
subsystem RAN nodes 102-104 may be in communication with a General
Packet Radio Service (GPRS) subsystem 107 or an EPC subsystem 109.
The GPRS subsystem 107 may be referred to as a 3GPP subsystem. It
should also be appreciated that the network may further comprise a
non-3GPP subsystem (e.g. a WiFi or Wireless Local Area Network
(WLAN) subsystem), although not illustrated in FIG. 1.
[0007] The UE 101 may be a device by which a subscriber may access
services offered by an operator's network and services outside the
operator's network to which the operator's radio access network and
core network provide access, e.g. access to the Internet. The UE
101 may be any device, mobile or stationary, enabled to communicate
in the communications network, for instance but not limited to e.g.
user equipment, mobile phone, smart phone, sensors, meters,
vehicles, household appliances, medical appliances, media players,
cameras, Machine to Machine (M2M) device, Device to Device (D2D)
device, Internet of Things (IoT) device or any type of consumer
electronic, for instance but not limited to television, radio,
lighting arrangements, tablet computer, laptop or Personal Computer
(PC). The UE 101 may be portable, pocket storable, hand held,
computer comprised, or vehicle mounted devices, enabled to
communicate voice and/or data, via the radio access network, with
another entity, such as another UE or a server.
[0008] The GPRS subsystem 107 may comprise a Gn/Gp SGSN 111, which
may be responsible for the delivery of data packets to and from the
UEs 101 within an associated geographical service area. The Gn/Gp
SGSN 111 may also be responsible for packet routing, transfer,
mobility management and connectivity management. The GPRS subsystem
107 may also include a Gateway GPRS Support Node (GGSN) 113, which
may be responsible for the interworking between the GPRS subsystem
107 and the PDN 105. Gn is an Internet Protocol (IP) based
interface between the SGSN and other SGSNs and (internal) GGSNs. Gn
uses the GPRS Tunneling Protocol (GTP) Protocol. Gp is an IP based
interface between internal SGSN and external GGSNs. Gp also uses
the GTP Protocol.
[0009] The EPC subsystem 109 may comprise a Mobility Management
Entity (MME) 115, which may be responsible for mobility management,
connectivity management, idle mode UE tracking, paging procedures,
attachment and activation procedures, and small data and message
transfer. The term mobility management node may be used when
referring to the MME 115. The EPC subsystem 109 may also comprise a
Serving Gateway (SGW) 117, which may be responsible for the routing
and forwarding of data packets. The EPC subsystem 109 may also
include a Packet data network Gateway (PGW, PDN GW) 119, which may
be responsible for providing connectivity from the UE 101 to one or
more PDN(s) 105. The PGW 119 may also be referred to as a Gn PGW, a
Gn-PGW or a GGSN/PGW. GGSN/PGW is a node in which the GGSN and PGW
are collocated, i.e. the node has both GGSN functionality and PGW
functionality. The SGW 117 may be referred to as a first gateway
and the PGW 119 may be referred to as a second gateway. Both the S4
SGSN 110 and the MME 115 may be in communication with a Home
Subscriber Server (HSS) 121, which may provide UE identification
information, an International Mobile Subscriber Identity (IMSI),
subscription information, etc. In some embodiments, the Gn/Gp SGSN
111 communicates with the HSS 121. The HSS 121 may be referred to
as a subscriber server. Another type of subscriber server is the
HLR 135 which is in communication with the Gn/Gp SGSN 111. It
should be appreciated that the EPC subsystem 109 may also comprise
a S4 SGSN 110, thereby allowing the GERAN 102 or UTRAN 103
subsystems to be accessed when the GPRS 107 is replaced by the EPC
109. S4 is an Interface in EPC between the SGSN 110 and the
SGW.
[0010] The handover procedure from non-3GPP access 123 to 3GPP
access 125 is illustrated in FIG. 2a and FIG. 2b. The non-3GPP
access 123 may be trusted or untrusted (trusted/untrusted), and the
term non-3GPP access 123 will be used in the following when
referring to any of the trusted or untrusted access. The term
non-3GPP access 123 may also be referred to as non-3GPP access
network, non-3GPP network, non-3GPP IP access, non-3GPP IP access
network, non-3GPP IP network, non-3GPP system etc. Similarly, the
term 3GPP access 125 may also be referred to as 3GPP access
network, 3GPP network, 3GPP IP access, 3GPP IP access network, 3GPP
IP network, 3GPP system etc. An example of a non-3GPP access 123
may be for example WiFi or WLAN. An example of a 3GPP access 125
may be for example GERAN 102, UTRAN 103 or E-UTRAN 104. So, when
any of the reference numbers 102, 103 or 104 is used it is also
referred to a 3GPP access 125. When the terms WiFi or WLAN is used,
is also referred to a non-3GPP access 123.
[0011] The non-3GPP access 124 may be represented by for example an
ePDG or a Trusted WLAN Access Network (TWAN). The ePDG is a gateway
in for the EPC 109 which secures the data transmission with the UE
101 connected to the EPC over an untrusted non-3GPP access 123. For
this purpose, the ePDG 123 acts as a termination node of IPsec
tunnels established with the UE 101.
[0012] 3GPP Technical Specification (TS) 23.402 defines the
handover procedure between GERAN/UTRAN 102, 103 and WiFi access. In
particular, handover from WiFi access to GERAN 102 or UTRAN 103
access connected to EPC 109 and based on S4 SGSN 110 from TS 23.402
is shown in FIG. 2a and FIG. 2b. FIG. 2a comprises steps 201-212
and FIG. 2b comprises steps 213-217. Steps 201-212 are to be
performed before steps 213-217, so FIG. 2b is a continuation of
FIG. 2a. The procedure in FIGS. 2a and 2b is applicable to a S4
SGSN 110 only. The AAA proxy 128 and the vPCRF 130v are involved in
the procedure only in case of a roaming scenario. AAA is short for
Authentication, authorization, and accounting and vPCRF is short
for visited Policy and Charging Rules Function.
[0013] FIG. 2a and FIG. 2b, are message passing diagrams of a
handover from 3GPP IP Access to UTRAN/GERAN 102, 103. As shown in
the FIGS. 2a and 2b, at WiFi to GERAN/UTRAN 102, 103 handover, an
attach procedure will be triggered first if the UE 101 is not
registered in GERAN/UTRAN 102, 103 yet. The S4 SGSN 110 then
performs an Update Location procedure to the HSS 121 and downloads
a user subscription profile. The UE 101 further sends an Activate
Packet Data Protocol (PDP) Context Request message with a Request
type=Handover. The S4 SGSN 110 will then trigger a Create Session
procedure with a Handover request message to the SGW 117 and the
PGW 119. Upon reception of the Create Session Response message, the
S4 SGSN 110 will trigger a Radio Access Bearer (RAB) establishment
to complete the PDP context activation. At the successful
completion of the PDP context establishment, the S4 SGSN 110 sends
a Modify Bearer Request message with a Handover Request message,
and the SGW 117 forwards the request to the PGW 119. The PGW 119
then switches the data path from WiFi to the GERAN/UTRAN 102, 103
interface.
[0014] PDP and PDN will now be shortly described. In LTE, bearers
are the tunnels used to connect a UE 101 to PDNs 105 such as the
Internet. In practice, bearers are concatenated tunnels that
connect the UE 101 to the PDN 105 through the PGW 119. In UTRAN and
GERAN, bearers are as PDP contexts. One PDP context connects to one
PDN location by default. In other words, a PDP context is an
association between a mobile host (represented by one IP address)
and a PDN 105 (represented by an Access Point Name (APN)). Each PDN
can be accessed via a gateway (for example a GGSN 113 or PGW 119).
A PDN connection may be described as the EPC equivalent of the GPRS
PDP context.
[0015] Each step in FIGS. 2a and 2b will now be described in more
detail, starting with FIG. 2a.
[0016] All steps outside steps 209-211 in FIG. 2a and steps 214-215
in FIG. 2b are common for architecture variants with GTP based
S5/S8 and PMIP based S5/S8. S5/S8 is the interface between the SGW
117 the PGW 119. In principle S5 and S8 is the same interface, the
difference is that S8 is used when roaming between different
operators while S5 is network internal. All steps 202-212 in FIG.
2a and steps 213-216 in FIG. 2b are common for architecture
variants with a GTP based S2b interface and PMIP based S2b
interface. S2b is an interface between the ePDG 123 and the PGW
119. S2b may be GTP based or PMIP based. The steps 207-212 in FIG.
2a and steps 213-217 in FIG. 2b shall be repeated for each PDN
connection that is being transferred from non-3GPP access, and can
occur in parallel for each PDN.
[0017] FIGS. 2a and 2b comprise at least some of the following
steps, which steps may be performed in any suitable order than
described below:
[0018] Step 201
[0019] This step is seen in FIG. 2a. The UE 101 uses a non-3GPP
access 123 and is being served by PGW 119 (as Proxy Mobile Internet
Protocol version 6 (PMIPv6) Local Mobility Anchor (LMA)). It is
assumed that while the UE 101 is served by the non-3GPP IP access
123, a PMIPv6 tunnel is established between the non-3GPP access 123
and the PGW 119 in the EPC 109.
[0020] Step 202
[0021] This step is seen in FIG. 2a. The UE 101 discovers the 3GPP
access 125 (UTRAN 103 or GERAN 102) and determines to transfer its
current sessions (i.e. handover) from the currently used non-3GPP
access 123 to the discovered 3GPP Access system 125.
[0022] Step 203
[0023] This step is seen in FIG. 2a. The UE 101 sends an Attach
Request message to the S4 SGSN 110. The message from the UE 101 is
routed by the 3GPP access 125 to the S4 SGSN 110. The S4 SGSN 110
receives the Attach Request message from the UE 101.
[0024] Step 204
[0025] This step is seen in FIG. 2a. The S4 SGSN 110 may contact
the HSS 121 and authenticate the UE 101. In FIG. 2a, the HSS 121 is
illustrated as HSS/AAA which involves that this node may be a HSS,
an AAA or a combined HSS and AAA node.
[0026] Step 205
[0027] This step is seen in FIG. 2a. The S4 SGSN 110 may perform a
location update procedure and subscriber data retrieval from the
HSS 121.
[0028] Step 206
[0029] This step is seen in FIG. 2a. The S4 SGSN 110 sends the
Attach Accept Request message to the UE 101 to indicate the
completion of the attach procedure. The UE 101 receives the Attach
Accept Request message from the S4 SGSN 110.
[0030] Step 207
[0031] This step is seen in FIG. 2a. The UE 101 initiates the
establishment of the primary PDP context by sending an Activate PDP
Context Request message to the S4 SGSN 110. The S4 SGSN 110
receives the Activate PDP Context Request message from the UE
101.
[0032] Step 208
[0033] This step is seen in FIG. 2a. The S4 SGSN 110 selects a SGW
117 and sends a Create Session Request message (comprising e.g. a
Handover indication, and other parameters) to the selected SGW 117.
The selected SGW 117 receives the Create Session Request message
from the S4 SGSN 110.
[0034] Step 209
[0035] This step is seen in FIG. 2a. The SGW 117 sends a Create
Session Request message to the PGW 119. The PGW 119 should not
switch the tunnel from non-3GPP access 123 to 3GPP access 125 at
this point. The PGW 119 receives a Create Session Request message
from the SGW 117.
[0036] Step 210
[0037] This step is seen in FIG. 2a. The PGW 119 may execute a
Policy and Charging Enforcement Function (PCEF) Initiated IP
Connectivity Access Network (IP CAN) Session Modification Procedure
with the PCRF 130 to report e.g. change in IP-CAN type.
[0038] Step 211
[0039] This step is seen in FIG. 2a. The PGW 119 responds with a
Create Session Response message to the SGW 117. The Create Session
Response message contains the IP address or the prefix that was
assigned to the UE 101 while it was connected to the non-3GPP
access 123. The SGW 117 receives the Create Session Response
message from the PGW 119.
[0040] Step 212
[0041] This step is seen in FIG. 2a. The SGW 117 returns a Create
Session Response message to the S4 SGSN 110. This message also
includes the IP address of the UE 101. This message also serves as
an indication to the S4 SGSN 110 that the S5 bearer setup and
update has been successful. The S4 SGSN receives the Create Session
Response message from the SGW 117.
[0042] Step 213
[0043] This step is seen in FIG. 2b. The rest of the PDP context
establishment is completed in step 213.
[0044] Step 214
[0045] This step is seen in FIG. 2b. The SGW 117 sends a Modify
Bearer Request message to the PGW 119 in the Visited Public Land
Mobile Network (VPLMN) or the Home Public Land Mobile Network
(HPLMN) including the Handover Indication flag that prompts the PGW
119 to tunnel packets from non-3GPP access 123 to 3GPP access 125
and immediately starts routing packets to the SGW 119 for the
default and any dedicated EPS bearers established. In case of
non-roaming or roaming with home routed traffic, this message is
sent to the PGW 119 in the HPLMN. In case of local breakout
traffic, the message is sent to the PGW 119 in the VPLMN. The PGW
119 receives the Modify Bearer Request message from the SGW
117.
[0046] Step 215
[0047] This step is seen in FIG. 2b. The PGW 119 acknowledges by
sending a Modify Bearer Response message to the SGW 117. The SGW
117 receives the Modify Bearer Response message from the PGW
119.
[0048] Step 216
[0049] This step is seen in FIG. 2b. The UE 101 sends and receives
data at this point via the 3GPP access 125.
[0050] Step 217
[0051] This step is seen in FIG. 2b. The PGW 119 shall initiate a
resource allocation deactivation procedure in the non-3GPP access
123.
[0052] In the current 3GPP standard, the handover between
UTRAN/GERAN 102, 103 and WiFi requires support of S4 SGSN. If Gn/Gp
SGSN is used, the handover between UTRAN/GERAN and WiFi is not
supported. However, most operators are keeping their Gn/Gp SGSN 111
deployments and are not upgrading their networks to support the
S4-based architecture. It is therefore currently not possible for
these operators to support mobility between WiFi and GERAN/UTRAN
102, 103 accesses. In addition, in case Gn/Gp SGSNs 111 are present
in the network, some mobility scenarios between LTE and WiFi are
not supported. For example, a scenario where the UE 101 starts in
GERAN/UTRAN 102, 103 (via Gn/Gp SGSN), then moves to LTE 104 and
then to WiFi is not supported using current standards. Currently,
when a handover to and from WiFi and 2G/3G 102, 103 takes place,
the Gn/Gp SGSN 1111 will create a new PDP context.
SUMMARY
[0053] An objective of embodiments herein is therefore to obviate
at least one of the above disadvantages and to provide improved
handover management.
[0054] According to a first aspect, the object is achieved by a
method in a Gn/Gp SGSN for providing handover management. The Gn/Gp
SGSN provides a handover for a UE to and from non-3GPP and 3GPP by
utilizing a PDP context that was previously created for the UE
during an attach procedure. The previously created PDP context is
for a previously serving PGW.
[0055] According to a second aspect, the object is achieved by a
method in a HLR for providing handover management. The HLR
receives, from a Gn/Gp SGSN, an identification of a PGW at a PDN,
connection establishment. The HLR stores the identification of the
PGW, and sends the identification of the PGW to a HSS.
[0056] According to a third aspect, the object is achieved by a
method, in a PGW for providing handover management. The PGW
receives, from a Gn/Gp SGSN, a Create PDP Context Request message
comprising an activated handover flag setting. The activated
handover flag setting indicates a handover request for a UE. The
handover is a non-3GPP to 3GPP handover.
[0057] According to a fourth aspect, the object is achieved by a
Gn/Gp SGSN for providing handover management. The Gn/Gp SGSN is
adapted to provide a handover for a UE to and from non-3GPP and
3GPP by utilizing a PDP context that was previously created for the
UE during an attach procedure. The previously created PDP context
is for a previously serving Packet data network Gateway.
[0058] According to a fifth aspect, the object is achieved by a HLR
for providing handover management. The HLR is adapted to receive,
from a Gn/Gp SGSN an identification of a PGW at a PDN, connection
establishment. The HLR is adapted to store the identification of
the PGW, and to send the identification of the PGW to a HSS.
[0059] According to a sixth aspect, the object is achieved by a PGW
for providing handover management. The PGW is adapted to receive,
from a Gn/Gp SGSN, a Create PDP Context Request message comprising
an activated handover flag setting. The activated handover flag
setting indicates a handover request for a UE. The handover is a
non-3GPP to 3GPP handover.
[0060] Thanks to the PDP context that was previously created for
the UE during an attach procedure, improved handover management is
provided.
[0061] Embodiments herein afford many advantages, of which a
non-exhaustive list of examples follows:
[0062] The embodiments herein may have the example advantage of
providing support for mobility between GERAN/UTRAN and WiFi when
the Gn/Gp SGSN is used. Another embodiment is that support of
mobility between E-UTRAN and WiFi is enabled in case Gn/Gp SGSNs
are used in the network, for example, in scenarios where the UE
connects in GERAN/UTRAN over the Gn/Gp SGSN, moves to E-UTRAN and
then to WiFi.
[0063] Another advantage of the embodiments herein is that when a
handover to and from WiFi and 2G/3G 102, 103 takes place, the Gn/Gp
SGSN 1111 does not need to create a new PDP context, i.e. a
previously created PDP context is utilized instead.
[0064] The embodiments herein are not limited to the features and
advantages mentioned above. A person skilled in the art will
recognize additional features and advantages upon reading the
following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0065] The foregoing will be apparent from the following more
particular description of the example embodiments, as illustrated
in the accompanying drawings in which like reference characters
refer to the same parts throughout the different views. The
drawings are not necessarily to scale, emphasis instead being
placed upon illustrating the example embodiments.
[0066] FIG. 1 is an example of a wireless communications
network.
[0067] FIG. 2 is a message passing diagram of a handover from
non-3GPP access to UTRAN/GERAN.
[0068] FIGS. 3-5 are message passing diagrams of a handover
procedure, using a Gn/Gp SGSN, between WiFi-2G/3G, according to
some of the example embodiments.
[0069] FIG. 6 is an example node configuration of a Gn/Gp SGSN,
according to some of the example embodiments.
[0070] FIG. 7 is an example node configuration of a HLR, according
to some of the example embodiments.
[0071] FIG. 8 is an example node configuration of a PGW, according
to some of the example embodiments.
[0072] FIG. 9 is a flow diagram of example operations which may be
taken by the Gn/Gp SGSN of FIG. 6, according to some of the example
embodiments.
[0073] FIG. 10 is a module diagram of modules which may perform at
least some of the operations illustrated in FIG. 9, according to
some of the example embodiments.
[0074] FIG. 11 is a flow diagram of example operations which may be
taken by the HLR of FIG. 7, according to some of the example
embodiments.
[0075] FIG. 12 is a module diagram of modules which may perform at
least some of the operations illustrated in FIG. 11, according to
some of the example embodiments.
[0076] FIG. 13 is a flow diagram of example operations which may be
taken by the PGW of FIG. 8, according to some of the example
embodiments.
[0077] FIG. 14 is a module diagram of modules which may perform at
least some of the operations illustrated in FIG. 13, according to
some of the example embodiments.
[0078] FIGS. 15a-b are flow charts illustrating example embodiments
of a method performed by a Gn/Gp SGSN.
[0079] FIG. 16 is a schematic block diagram illustrating example
embodiments of a Gn/Gp SGSN.
[0080] FIG. 17 is a flow chart illustrating example embodiments of
a method performed by a HLR.
[0081] FIG. 18 is a schematic block diagram illustrating example
embodiments of a HLR.
[0082] FIG. 19 is a flow chart illustrating example embodiments of
a method performed by a PGW.
[0083] FIG. 20 is a schematic block diagram illustrating example
embodiments of a PGW.
[0084] In the following description, for purposes of explanation
and not limitation, specific details are set forth, such as
particular components, elements, techniques, etc. In order to
provide a thorough understanding of the example embodiments.
However, it will be apparent to one skilled in the art that the
example embodiments may be practiced in other manners that depart
from these specific details. In other instances, detailed
descriptions of well-known methods and elements are omitted so as
not to obscure the description of the example embodiments. The
terminology used herein is for the purpose of describing the
example embodiments and is not intended to limit the embodiments
presented herein. It should be appreciated that the term user
equipment, UE and wireless device may be used interchangeably.
DETAILED DESCRIPTION
[0085] As mentioned above, currently, there are no procedures in
place for a Gn/Gp SGSN 111 to provide a handover for a UE 101 to
and from non-3GPP access 123 and 3GPP access 125, e.g. to and from
WiFi and 2G/3G. Currently, when such a procedure takes place, the
Gn/Gp SGSN 111 will create a new PDP context instead of using one
that was previously created for the UE 101 during an attach
procedure. A need therefore exists for a means for a Gn/Gp SGSN 111
to provide handover management for WiFi and 2G/3G in which a
previously created PDP context for a previously serving PGW 119 may
be utilized. The previously serving PGW 119 is a PGW which
previously served the UE 101.
[0086] Thus, the example embodiments presented herein provide a
means for a Gn/Gp SGSN 111 to provide handover management for WiFi
and 2G/3G 102, 103 in which a previously created PDP context for a
previously serving PGW 119 may be utilized. The example embodiments
have the example advantage of providing support for mobility
between GERAN/UTRAN 102, 103 and WiFi when the Gn/Gp SGSN 111 is
used. As a side effect, also support of mobility between E-UTRAN
104 and WiFi is enabled in case Gn/Gp SGSNs 111 are used in the
network, for example, in scenarios where the UE 101 connects in
GERAN/UTRAN 102, 103 over the Gn/Gp SGSN 111, moves to E-UTRAN 104
and then to WiFi.
[0087] The following three scenarios will now be described with
reference to FIGS. 3, 4, and 5: [0088] 1) 3GPP initial attach based
on Gn/Gp SGSN (FIG. 3). [0089] 2) 3GPP to non-3GPP handover based
on Gn/Gp SGSN (FIG. 4). [0090] 3) Non-3GPP to 3GPP handover based
on Gn/Gp SGSN (FIG. 5).
[0091] FIG. 3 illustrates scenario 1) with the 3GPP initial attach
based on the Gn/Gp SGSN 111, according to some of the example
embodiments. FIG. 3 uses an example where the 3GPP access 125 is
represented by UTRAN/GERAN 102, 103, so FIG. 3 is an example of
UTRAN/GERAN 102, 103 initial attach based on the Gn/Gp SGSN 111.
However, FIG. 3 is equally applicably to any other 3GPP initial
attach. In FIG. 3, the non-3GPP network 123 is represented by a
TWAN or ePDG, i.e. a TWAN or an ePDG or a combined TWAN and ePDG
node.
[0092] In general, steps 301-313 in FIG. 3 are the same as the
normal initial attach and the PDP Activation procedure based on the
Gn/Gp SGSN 111. Steps 314-315 in FIG. 3 are in order to support
handover from the UTRAN/GERAN to WiFi. The Gn/Gp SGSN 111 needs to
trigger the Update Location procedure over the Gr Interface as the
S4 SGSN 110 to register the PGW ID and Access Point Name (APN)
information on the HLR 135, and the HLR 135 needs to synchronize
with the HSS 121 for the EPS information. The PGW ID and APN
information may be referred to as Evolved Packet System (EPS)
information. The PGW ID may also be referred to as Gn-PGW ID or PGW
ID or PGW context. The APN may be a pre-existing IP address. Note
that in some deployments the HLR 135 and the HSS 121 may be
collocated. If the UE 101 later handovers from UTRAN/GERAN 102, 103
to WiFi, the AAA server will get the PGW ID and APN information
from the HSS 121. According to the current standard of TS 23.402,
if the UE 101 first registers via the Gn/Gp SGSN 111 and
establishes a PDN connection under GERAN/UTRAN 102, 103, and then
moves to E-UTRAN 104 (or GERAN/UTRAN 102, 103 served by the S4 SGSN
110), the PGW ID assigned to the PDN connection remains unknown to
the HSS 121, and further handover from 3GPP access 125 to WiFi will
not be possible. With the support of steps 314-315 in FIG. 3, such
limitation can be removed because the HLR/HSS 121, 135 has been
updated with the PGW ID at the PDN connection establishment via the
Gn/Gp SGSN 111.
[0093] Each step seen in FIG. 3 will now be described in detail.
The method in FIG. 3 comprises at least some of the following
steps, which steps may be performed in any suitable order than
described below:
[0094] Step 301
[0095] The UE 101 sends an Attach Request message to the Gn/Gp SGSN
111. The Gn/Gp SGSN 111 receives the Attach Request message.
[0096] Step 302
[0097] The Gn/Gp SGSN 111 sends an Update Location message to the
HLR 135, and the HLR 135 receives the Update Location message from
the Gn/Gp SGSN 111.
[0098] Step 303
[0099] The HLR 135 sends an Insert Subscriber Data (ISD) message to
the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the ISD message
from the HLR 135.
[0100] Step 304
[0101] The Gn/Gp SGSN 111 sends an ISD Acknowledgement (Ack)
message to the HLR 135 to acknowledge the receipt of the ISD
message in step 303. The HLR 135 receives the ISD Ack message from
the Gn/Gp SGSN 111.
[0102] Step 305
[0103] The HLR 135 sends an Update Location Ack message to the
Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the Update Location Ack
message from the HLR 135. The Update Location Ack message is a
response to the Update Location message in step 302.
[0104] Step 306
[0105] The Gn/Gp SGSN 111 sends an Attach Complete message to the
UE 101. The UE 101 receives the Attach Complete message from the
Gn/Gp SGSN 111. The Attach Complete message indicates that the
attach which was requested in step 301 has been completed.
[0106] Step 307
[0107] The UE 101 sends an Activate PDP Context Request message to
the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the Activate PDP
Context Request message from the UE 101.
[0108] Step 308
[0109] The Gn/Gp SGSN 111 sends a Create PDP Context Request
message to the PGW 119. The PGW 119 receives the Create PDP Context
Request message from the Gn/Gp SGSN 111.
[0110] Step 309
[0111] The PGW 119 sends a Create PDP Context Response message to
the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the Create PDP
Context Response message from the PGW 119.
[0112] Step 310
[0113] A RAB assignment is performed between the UE 101 and the
Gn/Gp SGSN 111.
[0114] Step 311
[0115] The Gn/Gp SGSN 111 may send an Update PDP Context Request
message to the PGW 119. This step is an optional step which is
indicated with the dotted arrow in FIG. 3. The PGW 119 may receive
an Update PDP Context Request message from the Gn/Gp SGSN 111.
[0116] Step 312
[0117] The PGW 119 may send an Update PDP Context Response message
to the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 may receive the Update
PDP Context Response message from the PGW 119. The Update PDP
Context Response message may be a response to the Update PDP
Context Request message in step 311. This is an optional step which
is indicated with the dotted arrow in FIG. 3.
[0118] Step 313
[0119] The Gn/Gp SGSN 111 sends an Activate PDP Context Accept
message to the UE 101. The UE 101 receives the Activate PDP Context
Accept message from the Gn/Gp SGSN 111. The Activate PDP Context
Accept message may be a response to the Activate PDP Context
Request message in step 307.
[0120] Step 314
[0121] The Gn/Gp SGSN 111 needs to update HLR 135 with the selected
PGW ID and APN. The Gn/Gp SGSN 111 sends an Update Location message
to the HLR 135. The HLR 135 receives the Update Location message
from the Gn/Gp SGSN 111. The Update Location message comprises EPS
information such as the PGW ID and APN.
[0122] Step 315
[0123] The HLR 135 sends the updated EPS information to the HSS
121, and the HSS 121 receives the updated EPS information. This may
also be described as the HLR 135 synchronizes the updated EPS
information with the HSS 121.
[0124] Step 316
[0125] The HLR 135 sends an Update Location Ack message to the
Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the Update Location Ack
message from the HLR 135. The Update Location Ack message may be a
response to the Update Location message in step 314 and a
confirmation of that the location information has been received and
successfully updated.
[0126] FIG. 4 illustrates scenario 2) with the 3GPP to non-3GPP
handover of a UE 101 based on the Gn/GP SGSN 111, according to some
of the example embodiments. FIG. 4 uses an example where the 3GPP
access 125 is represented by UTRAN/GERAN 102, 103, so FIG. 4 is an
example of UTRAN/GERAN 102, 103 to WiFi handover based on the Gn/Gp
SGSN 111. However, FIG. 4 is equally applicably to any other 3GPP
initial attach. In FIG. 4, the non-3GPP access 123 is represented
by a TWAN or ePDG, i.e. a TWAN or an ePDG or a combined TWAN and
ePDG node. The method in FIG. 4 comprises at least some of the
following steps, which steps may be performed in any suitable order
than described below:
[0127] Step 401
[0128] The UE 101 performs an Initial Attach and a PDP Context
Activation procedure based on the Gn/Gp SGSN 101 as described in
FIG. 3.
[0129] Step 402
[0130] The UE 101 decides handover to WiFi and performs a normal
Internet Key Exchange version 2 (IKEv2) access authentication
procedure. The AAA server will return the PGW ID to the ePDG 123.
The UE 101, the ePDG 123, the AAA/HSS 121 may be involved in the
access authentication procedure in step 402.
[0131] Step 403
[0132] At successful authentication, the ePDG 123 sends a Create
Session Request message to the PGW 119 as the normal 3GPP to WiFi
handover. The PGW 119 receives the Create Session Request message
from the ePDG 123. The Create Session Request message comprises a
handover flag setting which is activated, i.e. Handover
Indication=1. The number 1 indicates that the handover indication
is activated.
[0133] Step 404
[0134] The PGW 119 also searches the context to accept the
handover. In other words, the PGW 119 needs to check both the S5/S8
PDN context and the Gn/Gp PDP context which corresponds to the PDN
connection requested for handover of the UE 101 from GERAN/UTRAN
102, 103 to WiFi.
[0135] Step 405
[0136] The PGW 119 accepts the handover from GERAN/TRAN 102, 103 to
WiFi by replying by sending a Create Session Response message to
the ePDG 123. The ePDG 123 receives the Create Session Response
message from the PGW 119. The Create Session Response message is a
response to the Create Session Request message in step 403.
[0137] Step 406
[0138] The PGW 119 triggers the Gn/Gp PDP Context Deletion to the
Gn/Gp SGSN 111 with the cause code "RAT Changed from 3GPP to
non-3GPP" (this requires a new cause code in a GTP version 1
(GTPv1) protocol). RAT is short for Radio Access Technology. In
other words, the PGW 119 sends a Delete PDP Context Request message
to the Gn/Gp SGSN 111. The Delete PDP Context Request message
comprises an indication of that the RAT for the UE 101 has changed
from 3GPP to non-3GPP, e.g. from UTRAN/GERAN to WiFi. The Gn/Gp
SGSN 111 receives the Delete PDP Context Request message from the
PGW 119.
[0139] Step 407
[0140] The Gn/Gp SGSN 111 sends a Deactivate PDP Context Request
message to the UE 101. The UE 102 receives the Deactivate PDP
Context Request message from the Gn/Gp SGSN 111.
[0141] Step 408
[0142] The UE 101 sends a Deactivate PDP Context Response message
to the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the Deactivate
PDP Context Response message from the UE 101. The Deactivate PDP
Context Response message is a response to the Deactivate PDP
Context Request message in step 407 and indicates that the PDP
context has been deactivated, as requested.
[0143] Step 409
[0144] The Gn/Gp SGSN 111 sends a Delete PDP Context Response
message to the PGW 119. The PGW 119 receives the Delete PDP Context
Response message from the Gn/Gp SGSN 111. The Delete PDP Context
Response message is a response to the Delete PDP Context Request
message in step 406 and indicates that the PDP context has been
deleted, as requested.
[0145] Note that steps 406.about.409 may be repeated for several
PDP contexts to be deactivated. The PDP contexts correspond to the
PDN connection handed over to WiFi, as indicated with the dotted
box around steps 406-409 in FIG. 4.
[0146] Step 410
[0147] The PGW 119 may trigger dedicated bearer creation if there
are secondary PDP contexts to be handed over to WiFi. Thus, the PGW
119 may send a Create Bearer Request message to the ePDG 123. The
ePDG 124 receives the Create Bearer Request from the PGW 119. This
is an optional step which is indicated with the dotted arrow in
FIG. 4.
[0148] Step 411
[0149] The ePDG 123 may create the requested bearer and may send a
Create Bearer Response message to the PGW 119. The PGW 119 may
receive the Create Bearer Response message from the ePDG 123. The
Create Bearer Response message is a response to the Create Bearer
Request message in step 410. The Create Bearer Response message may
indicate that the bearer has been created, as requested.
[0150] FIG. 5 illustrates scenario 3) with the non-3GPP to 3GPP
handover based on the Gn/Gp SGSN 111, according to some of the
example embodiments. FIG. 5 uses an example where the 3GPP access
125 is represented by UTRAN/GERAN 102, 103 and where non-3GPP
access 123 is represented by WiFi, so FIG. 5 is an example of WiFi
to UTRAN/GERAN 102, 103 handover based on a Gn/Gp SGSN 111.
However, FIG. 5 is equally applicably to any other non-3GPP to 3GPP
handover. In FIG. 5, the non-3GPP access 123 is represented by a
TWAN or ePDG, i.e. a TWAN or an ePDG or a combined TWAN and ePDG
node. The method illustrated in FIG. 5 comprises at least some of
the following steps, which steps may be performed in any suitable
order than described below:
[0151] Step 501
[0152] The UE 101 has a PDN connection established over WiFi access
via the ePDG 123 and the PGW 119.
[0153] Step 502
[0154] The UE 101 decides to handover from WiFi access to
UTRAN/GERAN 102, 103 and performs a 3GPP attach procedure. The UE
101 sends an Attach Request message to the Gn/Gp SGSN 111. The
Gn/Gp SGSN 111 receives the Attach Request message from the UE
101.
[0155] Step 503
[0156] The Gn/Gp SGSN 111 sends an Update Location message to the
HLR 135. The HLR 135 receives the Update Location message from the
Gn/Gp SGSN 111.
[0157] Step 504
[0158] The HLR 135 retrieves the PGW ID from the HSS 119.
[0159] Step 505
[0160] The HLR 135 sends an ISD message comprising the PGW ID and
the APN to the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the ISDN
message from the HLR 135. In other words, the HLR 135 provides the
PGW ID and PLMN ID to the Gn/Gp SGSN 111, corresponding to an
already allocated PGW(s) 119.
[0161] Step 506
[0162] The Gn/Gp SGSN 111 sends an ISD Ack to the HLR 135. The HLR
135 receives the ISD Ack from the Gn/Gp SGSN 111. The ISD Ack is an
acknowledgement of the ISD message in step 505.
[0163] Step 507
[0164] The HLR 135 sends an Update Location Ack message to the
Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the Update Location Ack
message from the HLR 135. The Update Location Ack message is a
response to the Update Location message in step 503, acknowledges
that the Update Location message in step 503 has been received.
[0165] Step 508
[0166] The Gn/Gp SGSN 111 sends an Attach Complete message to the
UE 101. The UE 101 receives the Attach Complete message from the
Gn/Gp SGSN 111. The Attach Complete message is a response to the
Attach Request message in step 502, and indicates that the
requested attach is complete.
[0167] Step 509
[0168] The UE 101 sends an Activate PDP Context Request message
with a Handover Request as the normal WiFi to UTRAN/GERAN 102, 103
handover. Note that the UE 101 is not aware whether it is a S4 SGSN
110 or a Gn/Gp SGSN 111 it is sending the message to. The Gn/Gp
SGSN 111 needs to be able to process such Handover Request (not
supported by Gn/Gp SGSN today). The Gn/Gp SGSN 111 receives the
Activate PDP Context Request message from the UE 101.
[0169] Step 510
[0170] The Gn/Gp SGSN 111 needs to add a new extension to indicate
a Handover Request in the Create PDP Context Request message. Thus,
the Gn/Gp SGSN 11 sends the Create PDP Context Request message to
the PGW 119. The Create PDP Context Request message comprises an
activated handover flag setting, e.g. HO=1.
[0171] Step 511
[0172] The PGW 119 learns the non-3GPP to 3GPP handover request,
and finds the PDN context on the WiFi access to be handed over. The
PGW 119 replies to the Gn/Gp SGSN 111 with a Create PDP Context
Response message including the new extension to indicate to the
Gn/Gp SGSN 111 that the PGW 119 can support the non-3GPP to 3GPP
handover. The extension may be an activated handover flag setting,
e.g. HO=1. The Create PDP Context Response message comprises at
least part of the context for the Gn/Gp SGSN 111 which has been
identified by the PGW 119. The Gn/Gp SGSN 111 receives the Create
PDP Context Response message from the PGW 119. The Create PDP
Context Response message is a response to the Create PDP Context
Request message in step 510.
[0173] Step 512
[0174] The Gn/Gp SGSN 111 triggers a RAB Assignment procedure
towards the RAN, e.g. the Gn/Gp SGSN 111.
[0175] Step 513
[0176] At the successful RAB Assignment procedure, the Gn/Gp SGSN
111 needs to send an Update PDP Context Request message with the
new Handover extension to the PGW 119 even if there is no Quality
of Service (QoS) update if the Gn/Gp SGSN 111 learns that the PGW
119 can support the non-3GPP to 3GPP handover at step 511. The
handover extension may be the activated handover flag setting, e.g.
HO=1. Otherwise, the Gn/Gp SGSN 111 can follow the legacy behavior
of the PDP Activation. The PGW 119 receives the Update PDP Context
Request message from the Gn/Gp SGSN 111.
[0177] Step 514
[0178] The PGW 119 switches data path to UTRAN/GERAN access upon
reception of the Update PDP Context Request message with the
Handover extension in step 513. At this step, in order to reduce
packet drop rates, the PGW 119 shall run all the user traffic of
the handed over PDN connection over the primary PDP context
considering that the WLAN radio may have degraded already.
[0179] Step 515
[0180] The PGW 119 replies with an Update PDP Context Response
message to the Gn/Gp SGSN 111. The Gn/Gp SGSN 111 receives the
Update PDP Context Response message from the PGW 119. The Update
PDP Context Response message is a response to the Update PDP
Context Request message in step 513.
[0181] Step 516
[0182] The Gn/Gp SGSN 111 sends an Activate PDP Context Accept
message to the UE 101. The UE 101 receives the Activate PDP Context
Accept message from the Gn/Gp SGSN 111. The Activate PDP Context
Accept message is a response to the Activate PDP Context Request
message in step 509.
[0183] Step 517
[0184] The PGW 119 shall trigger the Secondary PDP Context
Activation procedure if there are the dedicated bearers established
for WiFi access before handover or depending on the active Policy
and Charging Control (PCC) rules.
[0185] Step 518
[0186] After the successful Secondary PDP Context Activation, the
PGW 119 shall remap the user traffics (which run on the dedicated
bears over WiFi access) onto the newly established Secondary PDP
contexts, i.e. remap some traffic of the PDN connection to the
secondary PDP context.
[0187] If the UE 101 has established a voice or video call at WiFi
access before the handover, the UTRAN/GERAN 102, 103 needs to have
a policy for how to support the voice or video call continuity
after handover. The UTRAN/GERAN RAN may not support voice or a
video radio bearer (Conversational QoS class). In that scenario,
when triggering the Secondary PDP Context Activation procedure, the
PGW 119 can decide to reduce the QoS level of the voice or video
bearers based on the operator policy, or even drop the video
traffic completely and only keep the voice traffic. The PGW 119 may
also install all the traffic on the default bearer (primary PDP
context) without triggering the Secondary PDP Context Activation.
That is the deviation compared with WiFi to LTE handover.
[0188] Example Node Configurations
[0189] FIG. 6 illustrates an example node configuration of the
Gn/Gp SGSN 111. The Gn/Gp SGSN 111 may perform some of the example
embodiments described herein. The Gn/Gp SGSN 111 may comprise radio
circuitry, a communication port or a receiving unit 601A and
transmitting unit 601B that may be configured to receive and/or
transmit communication data, instructions, messages and/or any
information related to handover management. It should be
appreciated that the radio circuitry, a communication port or a
receiving 601A and transmitting 601B units may be comprised as any
number of transceiving, receiving, and/or transmitting units,
modules or circuitry.
[0190] The Gn/Gp SGSN 111 may also comprise a processing unit 603,
processing module or processing circuitry which may be configured
to provide and retrieve handover related information as described
herein. The processing unit 603 may be any suitable type of
computation unit, for example, a microprocessor, digital signal
processor (DSP), field programmable gate array (FPGA), or
application specific integrated circuit (ASIC), or any other form
of circuitry. The Gn/Gp SGSN 111 may further comprise a memory 605,
memory unit or memory circuitry which may be any suitable type of
computer readable memory and may be of volatile and/or non-volatile
type. The memory 605 may be configured to store received,
transmitted, and/or measured data, device parameters, communication
priorities, any form of handover related information and/or
executable program instructions.
[0191] FIG. 7 illustrates an example node configuration of the HLR
135. The HLR 135 may perform some of the example embodiments
described herein. The HLR 135 may comprise radio circuitry, a
communication port or a receiving unit 701A and transmitting unit
701B that may be configured to receive and/or transmit
communication data, instructions, messages and/or any information
related to handover management. It should be appreciated that the
radio circuitry, a communication port or a receiving 701A and
transmitting 701B units may be comprised as any number of
transceiving, receiving, and/or transmitting units, modules or
circuitry.
[0192] According to some of the example embodiments, the
transmitting may be performed with the use of an update location
request message. It should also be appreciated that the HLR may
alternatively receive the identification of the PGW 119 from the
HSS 121. It should be appreciated that, according to some of the
example embodiments, the HLR 135 need not store the identification
of the PGW 119 but merely receive and then send the identification
to the HSS 121.
[0193] The HLR 135 may also comprise a processing unit 703,
processing module or processing circuitry which may be configured
to provide and retrieve HO related information as described herein.
The processing unit 703 may be any suitable type of computation
unit, for example, a microprocessor, DSP, FPGA, or ASIC or any
other form of circuitry. The HLR 135 may further comprise a memory
705, memory unit or memory circuitry which may be any suitable type
of computer readable memory and may be of volatile and/or
non-volatile type. The memory 705 may be configured to store
received, transmitted, and/or measured data, device parameters,
communication priorities, any form of handover related information
and/or executable program instructions.
[0194] FIG. 8 illustrates an example node configuration of the PGW
119. The PGW 119 may be a Gn-PGW 119, a GGSN or a combined GGSN and
PGW node (GGSN/PGW). The PGW 119 may perform some of the example
embodiments described herein. The PGW 119 may comprise radio
circuitry, a communication port or a receiving unit 801A and
transmitting unit 801B that may be configured to receive and/or
transmit communication data, instructions, messages and/or any
information related to handover management. It should be
appreciated that the radio circuitry, a communication port or a
receiving 801A and transmitting 801B units may be comprised as any
number of transceiving, receiving, and/or transmitting units,
modules or circuitry.
[0195] The PGW 119 may also comprise a processing unit 803,
processing module or processing circuitry which may be configured
to provide and retrieve handover related information as described
herein. The processing unit 803 may be any suitable type of
computation unit, for example, a microprocessor, DSP, FPGA, or ASIC
or any other form of circuitry. The PGW may further comprise a
memory 805, memory unit or memory circuitry which may be any
suitable type of computer readable memory and may be of volatile
and/or non-volatile type. The memory 805 may be configured to store
received, transmitted, and/or measured data, device parameters,
communication priorities, any form of handover related information
and/or executable program instructions.
[0196] Example Node Operations
[0197] FIG. 9 is a flow diagram depicting example operations which
may be taken by the Gn/Gp SGSN 111 as described herein for handover
management. The Gn/Gp SGSN 111 may be the Gn/Gp SGSN of FIG. 6. It
should also be appreciated that FIG. 9 comprises some operations
which are illustrated with a solid border and some operations which
are illustrated with a dashed border. The operations which are
comprised in a solid border are operations which are comprised in
the broadest example embodiment. The operations which are comprised
in a dashed border are example embodiments which may be comprised
in, or a part of, or are further operations which may be taken in
addition to the operations of the boarder example embodiments. It
should be appreciated that these operations need not be performed
in order. Furthermore, it should be appreciated that not all of the
operations need to be performed. The example operations may be
performed in any order and in any combination.
[0198] The example embodiments presented herein provide a means for
allowing a handover between WiFi and 2G/3G using a Gn/Gp SGSN 111
where the connectivity (e.g. PGW context, pre-existing IP address,
etc.) with a previously serving PGW 119 may be maintained. Thus,
the example embodiments prevent the need of continuously
establishing a new session after a handover procedure.
[0199] It shall be appreciated that a Gn/Gp SGSN 111 is a SGSN
which supports the Gn/Gp interface. It should be appreciated that
the example embodiments discussed herein for the SGSN 111 is with
the use of Gn/Gp and not S4.
[0200] The method in FIG. 9 comprises at least some of the
following steps, which steps may be performed in any suitable order
than described below:
[0201] Step 908
[0202] The Gn/Gp SGSN 111 may identify if the serving PGW 119
supports a Gn/Gp based handover.
[0203] Step 910
[0204] The Gn/Gp SGSN 111 may receive, from a UE 101, a PDP Context
Activation request message comprising a handover flag setting. The
UE 101 has sent the PDP Context Activation Request message to Gn/Gp
SGSN 111.
[0205] The Gn/Gp SGSN 111 sends the PGW 119 a message with the
handover flag activated, and the PGW 119 receives the message from
the Gn/Gp SGSN 111. If the Gn/Gp SGSN 111 receives a message back
with the flag activated, the Gn/Gp SGSN 111 knows that the serving
PGW 119 supports Gn/Gp handover and will therefore apply the
example embodiments described herein rather than legacy methods
where the Gn/Gp SGSN 111 creates a new PDP context for handover
procedures instead of using the identification of a previously
serving PGW 119.
[0206] Step 912
[0207] The Gn/Gp SGSN 111 may analyse the handover flag
setting.
[0208] Step 914
[0209] If the analyze of the handover flag in step 912 indicates
that the flag setting is activated, the Gn/Gp SGSN 111 may receive,
from the HLR 135, an identification of a PGW 119 serving the UE
101. The HLR 135 has sent the Identification of the PGW 119 to the
Gn/Gp SGSN 111.
[0210] It should further be appreciated that the received
information described in step 914 is provided along with
subscription data that is also received. It should be appreciated
that the receiving of such information is not dependent on the flag
setting. The Information may be received on a same information
Element (IE) as the subscription data or on a separate IE. It
should be appreciated that the identification of the PGW 119 and
the subscription data need not be received in separate
messages.
[0211] Step 915
[0212] If the analyze of the handover flag in step 912 indicates
that the flag setting is activated, the Gn/Gp SGSN 111 may send, to
the PGW 119 (the PGW 119 which was identified in step 914), a
message comprising an activated handover flag setting. The PGW 119
receives the message from the Gn/Gp SGSN 111.
[0213] Step 916
[0214] If the analyze of the handover flag in step 912 indicates
that the flag setting is activated, the Gn/Gp SGSN 111 may
establish a handover procedure with the serving PGW 119, i.e. the
PGW 119 to which the message in step 915 was transmitted.
[0215] Step 918
[0216] If the analyze of the handover flag in step 912 indicates
that the flag setting is no activated, the Gn/Gp SGSN 111 may
select a PGW 119 to serve the UE 101.
[0217] Step 920
[0218] If the analyze of the handover flag in step 912 indicates
that the flag setting is not activated, the Gn/Gp SGSN 111 may
send, to the HLR 135, an identification of the selected PGW 119
(the PGW 119 which was selected in step 918). The HLR 135 may
receive the Identification of the selected PGW 119 from the Gn/Gp
SGSN 111.
[0219] FIG. 10 illustrates a module diagram illustrating various
modules comprised in the Gn/Gp SGSN 111 which may be used in the
implementation of the broadest embodiment of FIG. 9. The modules in
FIG. 10 may perform at least some of the operations illustrated in
FIG. 9. The Gn/Gp SGSN 111 may comprise least one of the following
modules: a request receiving module 1010, an analyzing module 1012,
an Identification receiving module 1014, an establishing handover
module 1016, a selecting module 1018 and a sending module 1020. The
request receiving module 101 and the identification receiving
module 1014 may correspond to the receiving unit 601A in FIG. 6.
The analyzing module, the establishing handover module 1016 and the
selecting module 1018 may correspond to the processing unit 603 in
FIG. 6. The sending module 1020 may correspond to the transmitting
unit 601B in FIG. 6.
[0220] The example embodiments presented herein provide a means for
allowing a handover between WiFi and 2G/3G using a Gn/Gp SGSN 111
where the connectivity (e.g. PGW context, pre-existing IP address,
etc.) with a previously serving PGW 1119 may be maintained. Thus,
the example embodiments prevent the need of continuously
establishing a new session after a handover procedure.
[0221] It shall be appreciated that a Gn/Gp SGSN 111 is a SGSN
which supports the Gn/Gp interface. It should be appreciated that
the example embodiments discussed herein for the SGSN is with the
use of Gn/Gp and not S4.
[0222] It should further be appreciated that the received identity
of the PGW 119 is provided along with subscription data that is
also received. It should be appreciated that the receiving of such
information is not dependent on the flag setting. The Information
may be received on a same IE as the subscription data or on a
separate IE. It should be appreciated that the identification of
the PGW and the subscription data need not be received in separate
messages.
[0223] FIG. 11 is a flow diagram depicting example operations which
may be taken by the HLR 135 as described herein for handover
management. The HLR 135 may be the HLR 135 of FIG. 7. It should
also be appreciated that FIG. 11 comprises some operations which
are illustrated with a solid border and some operations which are
illustrated with a dashed border. The operations which are
comprised in a solid border are operations which are comprised in
the broadest example embodiment. The operations which are comprised
in a dashed border are example embodiments which may be comprised
in, or a part of, or are further operations which may be taken in
addition to the operations of the boarder example embodiments. It
should be appreciated that these operations need not be performed
in order. Furthermore, it should be appreciated that not all of the
operations need to be performed. The example operations may be
performed in any order and in any combination.
[0224] The method in FIG. 11 comprises at least some of the
following steps, which steps may be performed in any suitable order
than described below:
[0225] Step 1130
[0226] The HLR 135 may receive, from the Gn/Gp SGSN 111, serving
the UE 101, an ID of the PGW 119 which is also serving the UE 101.
The Gn/Gp SGSN 111 has sent the PGW ID to the HLR 135.
[0227] Step 1132
[0228] The HLR 135 may store the ID of the PGW 119.
[0229] Step 1134
[0230] The HLR 135 may send the ID of the PGW 119 to the HSS 121.
The HSS 121 receives the PGW ID from the HLR 135.
[0231] Step 1136
[0232] The HLR 135 may send, to the Gn/Gp SGSN 111, the ID of the
PGW 119 serving the UE 101 upon an establishment of a handover
procedure. The Gn/Gp SGSN 111 may receive the PGW ID from the HLR
135.
[0233] According to some of the example embodiments, the sending
may be performed with the use of an update location request
message. It should also be appreciated that the HLR 135 may
alternatively receive the Identification of the PGW 119 from the
HSS 121. It should be appreciated that, according to some of the
example embodiments, the HLR 135 need not store the identification
of the PGW 119 but merely receive and then send the identification
to the HSS 121.
[0234] FIG. 12 illustrates a module diagram illustrating various
modules comprised in the HLR 135 which may be used in the
implementation of the broadest embodiment of FIG. 11. The modules
in FIG. 12 may perform at least some of the operations illustrated
in FIG. 11. The HLR 135 may comprise at least one of the following
modules: receiving module 1230, storing module 1232 and sending
module 1234. The receiving module 1230 may correspond to the
receiving unit 701A in FIG. 7. The storing module 1232 may
correspond to the memory 705 in FIG. 7. The sending module 1234 may
correspond to the transmitting unit 701b in FIG. 7.
[0235] FIG. 13 is a flow diagram depicting example operations which
may be taken by the PGW 119 as described herein for handover
management. It should also be appreciated that FIG. 13 comprises
some operations which are illustrated with a solid border and some
operations which are illustrated with a dashed border. The
operations which are comprised in a solid border are operations
which are comprised in the broadest example embodiment. The
operations which are comprised in a dashed border are example
embodiments which may be comprised in, or a part of, or are further
operations which may be taken in addition to the operations of the
broader example embodiments. It should be appreciated that these
operations need not be performed in order. Furthermore, it should
be appreciated that not all of the operations need to be performed.
The example operations may be performed in any order and in any
combination. The method in FIG. 13 comprises at least some of the
following steps, which steps may be performed in any suitable order
than described below:
[0236] Step 1340
[0237] The PGW 119 may receive, from the Gn/Gp SGSN 111, serving
the UE 101, a Create PDP Context Request message comprising an
activated handover flag setting. The Gn/Gp SGSN 111 has sent the
Create PDP Context Request message to the PGW 119.
[0238] Step 1342
[0239] The PGW 119 may identify context corresponding to the PDN
connection of the UE 101 which is requested for the handover
procedure.
[0240] Step 1344
[0241] The PGW 119 may send at least part of the context to the
Gn/Gp SGSN 111 in a Create PDP Context Response message. The Gn/Gp
SGSN 111 receives the at least part of the context in the Create
PDP Context Response message. The Gn/Gp SGSN 11 may receive the at
least part of the context from the PGW 119.
[0242] FIG. 14 illustrates a module diagram illustrating various
modules comprised in the PGW 119 which may be used in the
Implementation of the broadest embodiment of FIG. 13. The modules
in FIG. 14 may perform at least some of the operations illustrated
in FIG. 13. The PGW 119 may comprise at least one of the following
modules: receiving module 1440, identifying module 1442 and sending
module 1444. The receiving module 1440 may correspond to the
receiving unit 801A in FIG. 8. The identifying module 1442 may
correspond to the processing unit 803 in FIG. 8. The sending module
1444 may correspond to the transmitting unit 801B in FIG. 8.
[0243] Further example embodiments comprise a method for
establishing a communication session from the UE 101 to the 3GPP
access 125. The method comprising establishing, through the 3GPP
access 125, the communication session between the UE 101 and the
PGW 119 where the Gn/Gp interface is used between the Gn/Gp SGSN
111 and the PGW 119. The method further comprising that the Gn/Gp
SGSN 111 provides information (e.g. the PGW ID) related to
3GPP-WLAN mobility to the HLR 135.
[0244] Further example embodiments also comprise a method in the
Gn/Gp SGSN 111 for performing a handover of a communication session
from a non-3GPP access 123 to a 3GPP access 125. The method
comprises establishing, through either the 3GPP access 125 or the
non-3GPP access 123, the communication session between the UE 101
and the PGW 119. During the handover of the communication session
from non-3GPP access 123 to GERAN/UTRAN access 102, 103, the Gn/Gp
SGSN 111 receives a request from the UE 101 to handover an existing
connection. The Gn/Gp SGSN 111 receives information related to
3GPP-WLAN mobility from the HLR 135, and the Gn/Gp SGSN 111
provides information over the Gn/Gp to the PGW 119 to indicate that
the request is referring to handover of an existing connection
[0245] Yet further example embodiments comprise a method in the PGW
119 for performing a handover of a communication session from the
non-3GPP access 123 to the 3GPP access 125. The method comprises
establishing, through either the 3GPP access 125 or the non-3GPP
access 123, the communication session between the UE 101 and the
PGW 119. During the handover of the communication session from the
non-3GPP access 123 to the GERAN/UTRAN access 102, 103, the PGW 119
receives a request from the Gn/Gp SGSN 111 over the Gn/Gp to
handover an existing connection. The PGW 119 identifies the exiting
PDN connection session corresponding to the non-3GPP access 123.
The PGW 119 preforms the handover of the communication session to
the PDP context session towards the Gn/Gp SGSN 111.
[0246] Another example embodiment comprises a method in the PGW 119
for performing a handover of a communication session from the
GERAN/UTRAN access 102, 103 to the non-3GPP access 123. The method
comprises establishing, through either the 3GPP access 125 or the
non-3GPP access 123, the communication session between the UE 101
and the PGW 119. During the handover of the communication session
from GERAN/UTRAN access 102, 103 to non-3GPP access 123, the PGW
119 receives a request from the non-3GPP access 123 to handover an
existing connection. The PGW 119 identifies the exiting PDP context
session corresponding to the source GERAN/UTRAN access 102, 103.
The PGW 119 preforms the handover of the communication session to
the PDN connection session towards the non-3GPP access 123.
[0247] The method described above will now be described seen from
the perspective of the Gn/Gp SGSN 111. FIGS. 15a and 5b are
flowcharts describing the present method performed by the Gn/Gp
SGSN 111 for providing handover management. FIG. 15b is a
continuation of FIG. 15a. FIG. 15a comprises steps 1501-1509 and
FIG. 15b comprises steps 1510-1517. The Gn/Gp SGSN 111 may be
configured for operation in a wireless network. The handover may be
from GERAN/UTRAN to WiFi, or from WiFi to GERAN/UTRAN, or from
GERAN/UTRAN to E-UTRAN, and then to WiFi. The method comprises at
least some of the following steps to be performed by the Gn/Gp SGSN
111, which steps may be performed in any suitable order than
described below:
[0248] Step 1501
[0249] This step is seen in FIG. 15a. The Gn/Gp SGSN 111 provides a
handover for a UE 101 to and from non-3GPP and 3GPP by utilizing a
PDP context that was previously created for the UE 101 during an
attach procedure. The previously created PDP context is for a
previously serving PGW 119.
[0250] Step 1502
[0251] This step is seen in FIG. 15a. This step corresponds to step
314 in FIG. 3. The Gn/Gp SGSN 111 may transmit an identification of
the PGW 119 to a HLR 135 at a PDN connection establishment.
[0252] Step 1503
[0253] This step is seen in FIG. 15a. This step corresponds to step
316 in FIG. 3. The Gn/Gp SGSN 111 may receive an acknowledgement of
the transmitted identification of the PGW 119 from the HLR 135.
[0254] Step 1504
[0255] This step is seen in FIG. 15a. This step corresponds to step
406 in FIG. 4. The Gn/Gp SGSN 111 may receive, from the PGW 119, a
Delete PDP Context Request message. The Delete PDP Context Request
message comprises an indication that a radio access type of the UE
101 has changed from 3GPP to non-3GPP.
[0256] The receiving, from the PGW 119, of the Delete PDP Context
Request message may be repeated for several PDP contexts which
correspond to a PDN connection handed over to non-3GPP.
[0257] The message described in step 1504 may be message 406 of the
FIG. 4 entitled `UTRAN/GERAN to WiFi Handover based on Gn/Gp
SGSN`.
[0258] Step 1505
[0259] This step is seen in FIG. 15a. This step corresponds to step
509 in FIG. 5 and step 910 in FIG. 9. The Gn/Gp SGSN 111 may
receive, from the UE 101, a PDP Context Activation Request message.
The PDP Context Activation Request message comprising a handover
flag setting.
[0260] Step 1506
[0261] This step is seen in FIG. 15a. This step corresponds to step
912 in FIG. 2. This step may be the same as step 1513 in FIG. 15b.
The Gn/Gp SGSN 111 may process the handover flag setting.
[0262] Step 1507
[0263] This step is seen in FIG. 15a. This step corresponds to step
510 in FIG. 5. The Gn/Gp SGSN 111 may send, to the PGW 119, a
Create PDP Context Request message comprising an activated handover
flag setting. The activated handover flag setting indicates a
handover request for the UE 101. The handover is a non-3GPP to 3GPP
handover.
[0264] An example of the message in step 1507 may be message 510 in
the FIG. 5 entitled `UTRAN/GERAN handover based on Gn/Gp SGSN.
[0265] Step 1508
[0266] This step is seen in FIG. 15a. This step corresponds to step
511 in FIG. 5. The Gn/Gp SGSN 111 may receive at least a part of a
context from the PGW 119 in a Create PDP Context Response message
to accept a handover request for the UE 101. The context
corresponds to a PDN connection of the UE 101 which is requested
for the handover.
[0267] Step 1509
[0268] This step is seen in FIG. 15a. This step corresponds to step
908 in FIG. 9. Based on a communication previously received from
the PGW 119, the Gn/Gp SGSN 111 may identify if the PGW 119
supports a Gn/Gp based handover.
[0269] Step 1510
[0270] This step is seen in FIG. 15b. This step corresponds to step
513 in FIG. 5. If the Gn/Gp SGSN 111 learns that the PGW 119 can
support the non-3GPP to 3GPP handover, the Gn/Gp SGSN 111 may send
an Update PDP Context Request message with an activated handover
flag setting to the PGW 119.
[0271] The Gn/Gp SGSN 111 may follow legacy behavior of PDP
Activation if the Gn/Gp SGSN 111 learns that the PGW 119 cannot
support the non-3GPP to 3GPP handover.
[0272] Step 1511
[0273] This step is seen in FIG. 15b. This step corresponds to step
515 in FIG. 5. The Gn/Gp SGSN 111 may receive an Update PDP Context
Response message from the PGW 119.
[0274] Step 1512
[0275] This step is seen in FIG. 15b. This step corresponds to step
307 in FIG. 3, step 509 in FIG. 5 and step 910 in FIG. 9. The Gn/Gp
SGSN 111 may receive, from the UE 10), a PDP Context Activation
request message. The PDP Context Activation Request message
comprising a handover flag setting.
[0276] Step 1513
[0277] This step is seen in FIG. 15b. This step corresponds to step
912 in FIG. 9. This step may be the same as step 1506 in FIG. 15a.
The Gn/Gp SGSN 111 may analyze the handover flag setting.
[0278] Step 1514
[0279] This step is seen in FIG. 15b. This step corresponds to step
914 in FIG. 9. If the handover flag setting is activated, the Gn/Gp
SGSN 111 may receive, from a HLR135 an identification of the PGW
119 serving the UE 101.
[0280] Step 1515
[0281] This step is seen in FIG. 15b. This step corresponds to step
916 in FIG. 9. The Gn/Gp SGSN 111 may establish a handover
procedure for the UE 101 with the identified serving PGW 119.
[0282] Step 1516
[0283] This step is seen in FIG. 15b. This step corresponds to step
918 in FIG. 9. If the handover flag setting is not activated, the
Gn/Gp SGSN 111 may select a PGW 119 to serve the UE 101.
[0284] Step 1517
[0285] This step is seen in FIG. 15b. This step corresponds to step
314 in FIG. 3 and step 920 in FIG. 9. The Gn/Gp SGSN 111 may send,
to the HLR 135, an identification of the selected PGW 119. The
identification of the PGW 119 may be a PGW Fully Qualified Domain
Name (FQDN), a PGW IP address, an APN and/or a PLMN identification.
The identification of the PGW 119 serving the wireless device 101
or the selected PGW may be a FQDN, a PGW IP address, an APN, and/or
a PLMN identification.
[0286] The message described in step 1517 is message 406 of the
FIG. 4 entitled `UTRAN/GERAN to WiFi Handover based on Gn/Gp
SGSN`.
[0287] The receiving in step 1514 and the establishing in step 1515
may further comprises sending, to the serving PGW 119, a Create PDP
Context Request message comprising an activated handover flag
setting. An example of this is message 510 in the FIG. 5 entitled
`UTRAN/GERAN handover based on Gn/Gp SGSN.
[0288] To perform the method steps shown in FIG. 15 for providing
handover management, the Gn/Gp SGSN 111 may comprise an arrangement
as shown in FIG. 16. The handover may be from GERAN/UTRAN to WiFi
or from WiFi to GERAN/UTRAN, or from GERAN/UTRAN to E-UTRAN, and
then to WiFi.
[0289] To perform the method steps shown in FIG. 15 for providing
handover management, the Gn/Gp SGSN 111 is adapted to, e.g. by
means of a providing module 1601, provide a handover for a UE 101
to and from non-3GPP and 3GPP by utilizing a PDP context that was
previously created for the UE 101 during an attach procedure. The
previously created PDP context is for a previously serving PGW 119.
The providing module 1601 may also be referred to as a providing
unit, a providing means, a providing circuit, means for providing
etc. The providing module 1601 may be a processor 1603 of the Gn/Gp
SGSN 111. The providing module 1601 of FIG. 16 may correspond to
the processing unit 803 of FIG. 8. The processor 1603 of FIG. 16
may correspond to the processing unit 803 of FIG. 8.
[0290] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of a transmitting module 1605, transmit an identification of the
PGW 119 to a HLR 135 at a PDN connection establishment. The
transmitting module 1605 may also be referred to as a transmitting
unit, a transmitting means, a transmitting circuit, means for
transmitting, output unit etc. The transmitting module 1605 may be
a transmitter, a transceiver etc. The transmitting module 1605 may
be a wireless transmitter of the Gn/Gp SGSN 111 of a wireless or
fixed communications system. The transmitting module 1605 of FIG.
16 may correspond to the transmitting unit 801B of FIG. 8 and the
sending module 1444 of FIG. 14.
[0291] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of a receiving module 1608, receive an acknowledgement of the
transmitted identification of the PGW 119 from the HLR 135. The
receiving module 1608 may also be referred to as a receiving unit,
a receiving means, a receiving circuit, means for receiving, input
unit etc. The receiving module 1608 may be a receiver, a
transceiver etc. The receiving module 1608 may be a wireless
receiver of the Gn/Gp SGSN 111 of a wireless or fixed
communications system. The receiving module 1608 of FIG. 16 may
correspond to the receiving unit 801A of FIG. 8 and the receiving
module 1440 of FIG. 14.
[0292] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the receiving module 1608, receive from the PGW 119, a Delete
PDP Context Request message. The Delete PDP Context Request message
may comprise an indication that a radio access type of the UE 101
has changed from 3GPP to non-3GPP.
[0293] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of a repeating module 1610, repeat the receiving, from the PGW 119,
of the Delete PDP Context Request message for several PDP contexts
which corresponds to a PDN connection handed over to non-3GPP. The
repeating module 1610 may also be referred to as a repeating unit,
a repeating means, a repeating circuit, means for repeating etc.
The repeating module 1610 may be the processor 1603 of the Gn/Gp
SGSN 111. The repeating module 1610 of FIG. 16 may correspond to
the processing unit 803 of FIG. 8.
[0294] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the receiving module 1608, receive, from the UE 101, a PDP
Context Activation request message. The PDP Context Activation
request message may comprise a handover flag setting.
[0295] The Gn/Gp SGSN 11 may be further adapted to, e.g. by means
of the processor 1603, process the handover flag setting.
[0296] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the transmitting module 1605, send, to the PGW 119, a Create PDP
Context Request message comprising an activated handover flag
setting. The activated handover flag setting may indicate a
handover request for the UE 101. The handover may be a non-3GPP to
3GPP handover.
[0297] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the receiving module 1608, receive at least a part of a context
from the PGW 119 in a Create PDP Context Response message to accept
a handover request for the UE 101. The context may correspond to a
PDN connection of the UE 101 which is requested for the
handover.
[0298] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of a Identifying module 1613, identify, based on a communication
previously received from the PGW 119, if the PGW 119 supports a
Gn/Gp based handover. The identifying module 1613 may also be
referred to as an identifying unit, an identifying means, an
identifying circuit, means for identifying etc. The identifying
module 1613 may be the processor 1603 of the Gn/Gp SGSN 111. The
identifying module 1613 of FIG. 16 may correspond to the processing
unit 803 of FIG. 8 and the identifying module 1442 of FIG. 14.
[0299] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the transmitting module 1605, send an Update PDP Context Request
message with an activated handover flag setting to the PGW 119 if
the Gn/Gp SGSN 111 leams that the PGW 119 can support the non-3GPP
to 3GPP handover. The Gn/Gp SGSN 111 may be adapted to follow
legacy behavior of PDP Activation if the Gn/Gp SGSN 111 leams that
the PGW 119 cannot support the non-3GPP to 3GPP handover.
[0300] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the receiving module 1608, receive an Update PDP Context
Response message from the PGW 119.
[0301] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the receiving module 1608, receive, from the UE 101, a PDP
Context Activation Request message. The PDP Context Activation
Request message may comprise a handover flag setting.
[0302] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of an analyzing module 1615, analyze the handover flag setting. The
analyzing module 1615 may also be referred to as an analyzing unit,
an analyzing means, an analyzing circuit, means for analyzing etc.
The analyzing module 1615 may be the processor 1603 of the Gn/Gp
SGSN 111. The analyzing module 1615 of FIG. 16 may correspond to
the processing unit 803 of FIG. 8.
[0303] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the receiving module 1608, if the handover flag setting is
activated, receive, from a HLR 135 an identification of the PGW 119
serving the UE 101.
[0304] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of an establishing module 1618, establish a handover procedure for
the UE 101 with the identified serving PGW 119. The establishing
module 1618 may also be referred to as an establishing unit, an
establishing means, an establishing circuit, means for establishing
etc. The establishing module 1618 may be the processor 1603 of the
Gn/Gp SGSN 111. The establishing module 1618 of FIG. 16 may
correspond to the processing unit 803 of FIG. 8.
[0305] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of an selecting module 1620, select, if the handover flag setting
is not activated, a PGW 119 to serve the UE 101. The selecting
module 1620 may also be referred to as a selecting unit, a
selecting means, a selecting circuit, means for selecting etc. The
selecting module 1620 may be the processor 1603 of the Gn/Gp SGSN
111. The selecting module 1620 of FIG. 16 may correspond to the
processing unit 803 of FIG. 8.
[0306] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the transmitting module 1605, send, to the HLR 135, an
identification of the selected PGW 119. The identification of the
PGW 119 may be a FQDN, a PGW IP, address, an APN, and/or a PLMN
identification.
[0307] The Gn/Gp SGSN 111 may be further adapted to, e.g. by means
of the transmitting module 1605, send, to the serving PGW 119, a
Create PDP Context Request message comprising an activated handover
flag setting.
[0308] The Gn/Gp SGSN 111 may further comprise a memory 1625
comprising one or more memory units. The memory 1625 is arranged to
be used to store data, received data streams, power level
measurements, handover flag, handover flag setting, request
messages, response messages, contexts, acknowledgements, PGW ID,
indications of that the RAT type has changed, information
indicating the selected PGW, threshold values, time periods,
configurations, schedulings, and applications to perform the
methods herein when being executed in the Gn/Gp SGSN 111. The
memory 1625 comprises instructions executable by the processor
1603. The memory 1625 of FIG. 16 may correspond to the memory 805
in FIG. 8.
[0309] Those skilled in the art will also appreciate that the
providing module 1601, the transmitting module 1605, the receiving
module 1608, the repeating module 1610, the identifying module
1613, the analysing module 1615, the establishing module 1618 and
the selecting module 1620 described above may refer to a
combination of analog and digital circuits, and/or one or more
processors configured with software and/or firmware, e.g. stored in
a memory, that when executed by the one or more processors such as
the processor 1603 perform as described above. One or more of these
processors, as well as the other digital hardware, may be included
in a single application-specific integrated circuit (ASIC), or
several processors and various digital hardware may be distributed
among several separate components, whether individually packaged or
assembled into a system-on-a-chip (SoC).
[0310] In some embodiments, a first computer program may comprise
instructions which, when executed on at least one processor, cause
the at least one processor to carry out the method steps 1501-1517.
A first carrier may comprise the first computer program, and the
first carrier is one of an electronic signal, optical signal, radio
signal or computer readable storage medium.
[0311] The method described above will now be described seen from
the perspective of the HLR 135. FIG. 17 is a flowchart describing
the present method performed by the HLR 135 for providing handover
management. The handover may be from GERAN/UTRAN to WiFi, or from
WiFi to GERAN/UTRAN, or from GERAN/UTRAN to E-UTRAN, and then to
WiFi. The HLR 135 may be configured for operation in a wireless
network. The method comprises at least some of the following steps
to be performed by the HLR 135, which steps may be performed in any
suitable order than described below:
[0312] Step 1701
[0313] This step corresponds to step 314 in FIG. 3 and step 1130 in
FIG. 11. The HLR 135 receives, from a Gn/Gp SGSN 111 an
identification of a PGW 119 at a PDN connection establishment.
[0314] Step 1702
[0315] This step corresponds to step 1132 in FIG. 11. The HLR 135
stores the identification of the PGW 119.
[0316] Step 1703
[0317] This step corresponds to step 315 in FIG. 3 and step 1134 in
FIG. 11. The HLR 135 sends the identification of the PGW 119 to a
HSS 121.
[0318] Step 1704
[0319] This step corresponds to step 1136 in FIG. 11. The HLR 135
may send, to the Gn/Gp SGSN 111, the identification of the PGW 119
serving the UE 101 upon an establishment of a handover
procedure.
[0320] It should be appreciated that the Gn/Gp SGSN 111 of example
step 1704 may or may not be the same Gn/Gp SGSN as described
earlier, e.g. In relation to FIG. 15.
[0321] Step 1705
[0322] This step corresponds to step 316 in FIG. 3. The HLR 135 may
transmit an acknowledgement of the received identification of the
PGW 119 to the Gn/Gp SGSN 119.
[0323] Step 1706
[0324] This step corresponds to step 504 in FIG. 5. When the UE 101
has decided to handover from non-3GPP to 3GPP, the HLR 135 may
retrieve the identification of an already allocated PGW 119 from a
HSS 121. The identification of the PGW 119 may be a FQDN, a PGW IP
address, an APN, and/or a PLMN identification.
[0325] To perform the method steps shown in FIG. 17 for providing
handover management, the HLR 135 may comprise an arrangement as
shown in FIG. 18. The handover may be from GERAN/UTRAN to WiFi, or
from WiFi to GERAN/UTRAN, or from GERAN/UTRAN to E-UTRAN, and then
to WiFi.
[0326] To perform the method steps shown in FIG. 17 for providing
handover management, the HLR 135 is adapted to, e.g. by means of a
receiving module 1801, receive, from a Gn/Gp SGSN 111 an
identification of a PGW 119 at a PDN connection establishment. The
receiving module 1801 may also be referred to as a receiving unit,
a receiving means, a receiving circuit, means for receiving, input
unit etc. The receiving module 1801 may be a receiver, a
transceiver etc. The receiving module 1801 may be a wireless
receiver of the HLR 135 of a wireless or fixed communications
system. The receiving module 1801 of FIG. 18 may correspond to the
receiving unit 701A in FIG. 7 and the receiving module 1230 in FIG.
12.
[0327] The HLR 135 is further adapted to, e.g. by means of a
storing module 1803, store the identification of the PGW 119. The
storing module 1803 may also be referred to as a storing unit, a
storing means, a storing circuit, means for storing etc. The
storing module 1803 may be a processor 1805 of the HLR 135. The
storing module 1803 of FIG. 18 may correspond to the processing
unit 703 of FIG. 7 and the storing module 1232 of FIG. 12. The
processor 1805 of FIG. 18 may correspond to the processing unit 703
in FIG. 7.
[0328] The HLR 135 is adapted to, e.g. by means of a transmitting
module 1808, send the Identification of the PGW 119 to a HSS 121.
The transmitting module 1808 may also be referred to as a
transmitting unit, a transmitting means, a transmitting circuit,
means for transmitting, output unit etc. The transmitting module
1808 may be a transmitter, a transceiver etc. The transmitting
module 1808 may be a wireless transmitter of the HLR 135 of a
wireless or fixed communications system. The transmitting module
1808 of FIG. 18 may correspond to the transmitting unit 701B of
FIG. 7 and the sending module 1234 of FIG. 12.
[0329] The HLR 135 may be further adapted to, e.g. by means of the
transmitting module 1808, send, to the Gn/Gp SGSN 111, the
identification of the PGW 119 serving the UE 101 upon an
establishment of a handover procedure.
[0330] The HLR 135 may be further adapted to, e.g. by means of the
transmitting module 1808, transmit an acknowledgement of the
received identification of the PGW 119 to the Gn/Gp SGSN 119.
[0331] The HLR 135 may be further adapted to, e.g. by means of a
retrieving module 1810, retrieve, when the UE 101 has decided to
handover from non-3GPP to 3GPP, the identification of an already
allocated PGW 119 from a HSS 121. The Identification of the PGW 119
may be a FQDN, a PGW IP address, an APN, and/or a PLMN
identification. The retrieving module 1810 may also be referred to
as a retrieving unit, a retrieving means, a retrieving circuit,
means for retrieving etc. The retrieving storing module 1810 may be
the processor 1805 of the HLR 135. The retrieving module 1810 of
FIG. 18 may correspond to the processing unit 705 of FIG. 7.
[0332] The HLR 135 may further comprise a memory 1813 comprising
one or more memory units. The memory 1813 is arranged to be used to
store data, received data streams, power level measurements,
handover flag, handover flag setting, request messages, response
messages, contexts, acknowledgements, PGW ID, indications of that
the RAT type has changed, information indicating the selected PGW,
threshold values, time periods, configurations, schedulings, and
applications to perform the methods herein when being executed in
the HLR 135. The memory 1813 comprises instructions executable by
the processor 1805. The memory 1813 of FIG. 18 may correspond to
the memory 705 in FIG. 7.
[0333] Those skilled in the art will also appreciate that the
receiving module 1801, the storing module 1803, the transmitting
module 1808 and the retrieving module 1810 described above may
refer to a combination of analog and digital circuits, and/or one
or more processors configured with software and/or firmware, e.g.
stored in a memory, that when executed by the one or more
processors such as the processor 1805 perform as described above.
One or more of these processors, as well as the other digital
hardware, may be included in a single ASIC, or several processors
and various digital hardware may be distributed among several
separate components, whether individually packaged or assembled
into a SoC.
[0334] In some embodiments, a second computer program may comprise
instructions which, when executed on at least one processor, cause
the at least one processor to carry out the method steps 1701-1706.
A second carrier may comprise the second computer program, and the
second carrier is one of an electronic signal, optical signal,
radio signal or computer readable storage medium.
[0335] The method described above will now be described seen from
the perspective of the PGW 119. FIG. 19 is a flowchart describing
the present method performed by the PGW 119 for providing handover
management. The handover may be from GERAN/UTRAN to WiFi, or from
WiFi to GERAN/UTRAN, or from GERAN/UTRAN to E-UTRAN, and then to
WiFi. The PGW 119 may be configured for operation in a wireless
network. The method comprises at least some of the following steps
to be performed by the PGW 119, which steps may be performed in any
suitable order than described below:
[0336] Step 1901
[0337] This step corresponds to step 510 in FIG. 5 and step 1340 in
FIG. 13. The PGW 119 receives, from a Gn/Gp SGSN 111, a Create PDP
Context Request message comprising an activated handover flag
setting. The activated handover flag setting indicates a handover
request for a UE 101. The handover is a non-3GPP to 3GPP
handover.
[0338] Step 1902
[0339] This step corresponds to step 1342 in FIG. 13. The PGW 119
may identify a context corresponding to a PDN connection of the UE
101 which is requested for the handover.
[0340] Step 1903
[0341] This step corresponds to step 511 in FIG. 5 and step 1344 in
FIG. 13. The PGW 119 may send at least part of the context to the
Gn/Gp SGSN 111 in a Create PDP Context Response message to accept
the handover request for the UE 101.
[0342] Step 1904
[0343] This step corresponds to step 406 in FIG. 4. The PGW 119 may
transmit, to the Gn/Gp SGSN 111, a Delete PDP Context Request
message. The Delete PDP Context Request message may comprise an
indication that a radio access type of the UE 101 has changed from
3GPP to non-3GPP. The transmitting, to the Gn/Gp SGSN 119, the
Delete PDP Context Request message may be repeated for several PDP
contexts which correspond to a PDN connection handed over to
non-3GPP.
[0344] Step 1905
[0345] This step corresponds to step 513 in FIG. 5. If the PGW 119
can support the non-3GPP 10 to 3GPP handover, the PGW 119 may
receive an Update PDP Context Request message with the activated
handover flag setting from the Gn/Gp SGSN 111.
[0346] Step 1906
[0347] This step corresponds to step 514 in FIG. 5. The PGW 119 may
switch a data path from non-3GPP to 3GPPG upon receipt of the
Update PDP Context Request message with the activated handover flag
setting.
[0348] Step 1907
[0349] This step corresponds to step 515 in FIG. 5. The PGW 119 may
transmit an Update PDP Context Response message to the Gn/Gp SGSN
111.
[0350] Step 1908
[0351] This step corresponds to step 916a in FIG. 9. The PGW 119
may establish a handover procedure for the UE 101 with the Gn/Gp
SGSN 111.
[0352] To perform the method steps shown in FIG. 19 for providing
handover management, the PGW 119 may comprise an arrangement as
shown in FIG. 20. The handover may be from GERAN/UTRAN to WiFi, or
from WiFi to GERAN/UTRAN, or from GERAN/UTRAN to E-UTRAN, and then
to WiFi.
[0353] To perform the method steps shown in FIG. 19 for providing
handover management, the PGW 119 is adapted to, e.g. by means of a
receiving module 2001, receive, from a Gn/Gp SGSN 111 a Create PDP
Context Request message comprising an activated handover flag
setting. The activated handover flag setting indicates a handover
request for a UE 101. The handover is a non-3GPP to 3GPP handover.
The receiving module 2001 may also be referred to as a receiving
unit, a receiving means, a receiving circuit, means for receiving,
input unit etc. The receiving module 2001 may be a receiver, a
transceiver etc. The receiving module 2001 may be a wireless
receiver of the PGW 119 of a wireless or fixed communications
system. The receiving module 2001 of FIG. 20 may correspond to the
receiving unit 601A in FIG. 6 and the request receiving module 1010
in FIG. 10.
[0354] The PGW 119 may be further adapted to, e.g. by means of an
Identifying module 2005, identify a context corresponding to a PDN
connection of the UE 101 which is requested for the handover. The
identifying module 2005 may also be referred to as an identifying
unit, an identifying means, an identifying circuit, means for
identifying etc. The identifying module 2005 may be a processor
2008 of the PGW 119. The identifying module 2005 of FIG. 20 may
correspond to the processing unit 603 of FIG. 6 and the
identification receiving module 1014 in FIG. 10. The processor 2008
of FIG. 20 may correspond to the processing unit 603 in FIG. 6 and
the analyzing module 1012 in FIG. 10.
[0355] The PGW 119 may be further adapted to, e.g. by means of a
transmitting module 2010, send at least part of the context to the
Gn/Gp SGSN 111 in a Create PDP Context Response message to accept
the handover request for the UE 101. The transmitting module 2010
may also be referred to as a transmitting unit, a transmitting
means, a transmitting circuit, means for transmitting, output unit
etc. The transmitting module 2010 may be a transmitter, a
transceiver etc. The transmitting module 2010 may be a wireless
transmitter of the PGW 119 of a wireless or fixed communications
system. The transmitting module 2010 of FIG. 20 may correspond to
the transmitting unit 601B of FIG. 6 and the sending module 1020 of
FIG. 10.
[0356] The PGW 119 may be further adapted to, e.g. by means of the
transmitting module 2010, transmit, to the Gn/Gp SGSN 111, a Delete
PDP Context Request message. The Delete PDP Context Request message
comprises an indication that a radio access type of the UE 101 has
changed from Third Generation Partnership Project, 3GPP, to
non-3GPP.
[0357] The PGW 119 may be further adapted to, e.g. by means of a
repeating module 2013, repeat the transmission, to the Gn/Gp SGSN
119, of the Delete PDP Context Request message for several PDP
contexts which corresponds to a PDN connection handed over to
non-3GPP. The repeating module 2013 may also be referred to as a
repeating unit, a repeating means, a repeating circuit, means for
repeating etc. The repeating module 2013 may be the processor 2008
of the PGW 119. The repeating module 2013 may correspond to the
processing unit 603 of FIG. 6.
[0358] The PGW 119 may be further adapted to, e.g. by means of the
receiving module 2001, receive, if the PGW 119 can support the
non-3GPP to 3GPP handover, an Update PDP Context Request message
with the activated handover flag setting from the Gn/Gp SGSN
111.
[0359] The PGW 119 may be further adapted to, e.g. by means of a
switching module 2015, switch a data path from non-3GPP to 3GPPG
upon receipt of the Update PDP Context Request message with the
activated handover flag setting. The switching module 2015 may also
be referred to as a switching unit, a switching means, a switching
circuit, means for switching etc. The switching module 2015 may be
the processor 2008 of the PGW 119. The switching module 2015 of
FIG. 20 may correspond to the processing unit 603 of FIG. 6.
[0360] The PGW 119 may be further adapted to, e.g. by means of the
transmitting module 2010, transmit an Update PDP Context Response
message to the Gn/Gp SGSN 111.
[0361] The PGW 119 may be further adapted to, e.g. by means of an
establishing module 2018, establish a handover procedure for the UE
101 with the Gn/Gp SGSN 111. The establishing module 2018 may also
be referred to as an establishing unit, an establishing means, an
establishing circuit, means for establishing etc. The establishing
module 2018 may be the processor 2008 of the PGW 119. The
establishing module 2018 of FIG. 20 may correspond to the
processing unit 603 of FIG. 6 and the establishing HO module 1016
of FIG. 10.
[0362] The PGW 119 may further comprise a memory 2020 comprising
one or more memory units. The memory 2020 is arranged to be used to
store data, received data streams, power level measurements,
handover flag, handover flag setting, request messages, response
messages, contexts, acknowledgements, PGW ID, indications of that
the RAT type has changed, information indicating the selected PGW,
threshold values, time periods, configurations, schedulings, and
applications to perform the methods herein when being executed in
the PGW 119. The memory 2020 comprises instructions executable by
the processor 2008. The memory 2020 of FIG. 20 may correspond to
the memory 605 of FIG. 6.
[0363] Those skilled in the art will also appreciate that the
receiving module 2001, the identifying module 2003, the
transmitting module 2010, the repeating module 2013, the switching
module 2015 and the establishing module 2018 the described above
may refer to a combination of analog and digital circuits, and/or
one or more processors configured with software and/or firmware,
e.g. stored in a memory, that when executed by the one or more
processors such as the processor 2008 perform as described above.
One or more of these processors, as well as the other digital
hardware, may be included in a single ASIC, or several processors
and various digital hardware may be distributed among several
separate components, whether individually packaged or assembled
into a SoC.
[0364] In some embodiments, a third computer program may comprise
instructions which, when executed on at least one processor, cause
the at least one processor to carry out the method steps 1901-1908.
A third carrier may comprise the third computer program, and the
third carrier is one of an electronic signal, optical signal, radio
signal or computer readable storage medium.
[0365] The present mechanism for providing handover management may
be implemented through one or more processors, such as a processor
1603 in the Gn/Gp SGSN arrangement depicted in FIG. 16, a processor
1805 in the HLR arrangement depicted in FIG. 18 and a processor
2008 in the PGW arrangement depicted in FIG. 20, together with
computer program code for performing the functions of the
embodiments herein. The processor may be for example a Digital
Signal Processor (DSP), Application Specific Integrated Circuit
(ASIC) processor, Field-programmable gate array (FPGA) processor or
microprocessor. The program code mentioned above may also be
provided as a computer program product, for instance in the form of
a data carrier carrying computer program code for performing the
embodiments herein when being loaded into at least one of the Gn/Gp
SGSN, the HLR 135 and the PGW 119. One such carrier may be in the
form of a CD ROM disc. It is however feasible with other data
carriers such as a memory stick. The computer program code can
furthermore be provided as pure program code on a server and
downloaded to at least one of the Gn/Gp SGSN, the HLR 135 and the
PGW 119.
[0366] A wireless communications system may feature the Gn/Gp SGSN
111, the HLR 135 and the PGW 119 described above for WiFi-2G/3G
handover management.
[0367] Summarized, in the current 3GPP standard, the handover
between UTRAN/GERAN 102, 103 and WiFi requires support of the S4
SGSN 110. If the Gn/Gp SGSN 111 is used, the handover between
UTRAN/GERAN 102, 103 and WiFi is not supported. However, most
operators are keeping their Gn/Gp deployments and are not upgrading
their networks to support the S4-based architecture. It is
currently not possible for these operators to support mobility
between WiFi and GERAN/UTRAN 102, 103 accesses. In addition, in
case Gn/Gp SGSNs 111 are present in the network some mobility
scenarios between LTE 104 and WiFi are not supported. For example,
a scenario where the UE 101 starts in GERAN/UTRAN 102, 103 (via the
Gn/Gp SGSN 111), then moves to LTE 104 and then to WiFi is not
supported using current standards.
[0368] A need therefore exists for a means for a Gn/Gp SGSN 111 to
provide handover management for WiFi and 2G/3G in which a
previously created PDP context for a previously serving PGW 119 may
be utilized. The example embodiments herein enable support of
mobility between GERAN/UTRAN 102, 103 and WiFi by adding the
following features: [0369] The Gn/Gp SGSN 111 provides handover
related information (e.g. PGW ID) to HLR 135 when the UE 101 is
connecting. [0370] The Gn/Gp SGSN 111 receives handover related
information from the UE 101 and from the HLR 135 when the UE 101
moves from WLAN to GERAN/UTRAN 102, 103. [0371] The PGW 119
performs handover of sessions between S2a/S2b interfaces and Gn/Gp
interfaces and informs the Gn/Gp SGSN 111 of the handover of the UE
101 from GERAN/UTRAN 102, 103 to WLAN.
[0372] Support for mobility between GERAN/UTRAN 102, 103 and WiFi
when the Gn/Gp SGSN 111 is used. As a side effect, also support of
mobility between E-UTRAN 104 and WiFi is enabled in case Gn/Gp
SGSNs 111 are used in the network, e.g. scenarios where the UE 101
connects in GERAN/UTRAN 102, 103 over the Gn/Gp SGSN 111, moves to
E-UTRAN 104 and then to WiFi.
[0373] Example embodiments presented herein are directed towards a
means for a Gn/Gp SGSN 111 to provide handover management for WiFi
and 2G/3G in which a previously created PDP context for a
previously serving PGW 119 may be utilized. In order to provide a
better explanation of the example embodiments presented herein, a
problem will first be identified and discussed.
[0374] Example embodiments presented herein are directed towards a
Gn/Gp SGSN 111, a HLR 135 and a PGW 119, and corresponding methods
therein, for WiFi-2G/3G handover management.
[0375] The description of the example embodiments provided herein
have been presented for purposes of illustration. The description
is not intended to be exhaustive or to limit example embodiments to
the precise form disclosed, and modifications and variations are
possible in light of the above teachings or may be acquired from
practice of various alternatives to the provided embodiments. The
examples discussed herein were chosen and described in order to
explain the principles and the nature of various example
embodiments and its practical application to enable one skilled in
the art to utilize the example embodiments in various manners and
with various modifications as are suited to the particular use
contemplated. The features of the embodiments described herein may
be combined in all possible combinations of methods, apparatus,
modules, systems, and computer program products. It should be
appreciated that the example embodiments presented herein may be
practiced in any combination with each other. Therefore, the above
embodiments should not be taken as limiting the scope of the
embodiments, which is defined by the appending claims.
[0376] It should be noted that the word "comprising" does not
necessarily exclude the presence of other elements or steps than
those listed and the words "a" or "an" preceding an element do not
exclude the presence of a plurality of such elements. It should
further be noted that any reference signs do not limit the scope of
the claims, that the example embodiments may be implemented at
least in part by means of both hardware and software, and that
several "means", "units" or "devices" may be represented by the
same item of hardware.
[0377] The term "adapted to" used herein may also be referred to as
"arranged to", "configured to", "capable of" or "operative to".
[0378] Also note that terminology such as user equipment should be
considered as non-limiting. A device or user equipment as the term
is used herein, is to be broadly interpreted to include a
radiotelephone having ability for Internet/intranet access, web
browser, organizer, calendar, a camera (e.g., video and/or still
image camera), a sound recorder (e.g., a microphone), and/or Global
Positioning System (GPS) receiver; a Personal Communications System
(PCS) user equipment that may combine a cellular radiotelephone
with data processing; a Personal Digital Assistant (PDA) that can
include a radiotelephone or wireless communication system; a
laptop; a camera (e.g., video and/or still image camera) having
communication ability; and any other computation or communication
device capable of transceiving, such as a personal computer, a home
entertainment system, a television, etc. It should be appreciated
that the term user equipment may also comprise any number of
connected devices. Furthermore, it should be appreciated that the
term user equipment shall be interpreted as defining any device
which may have an internet or network access.
[0379] The various example embodiments described herein are
described in the general context of method steps or processes,
which may be implemented in one aspect by a computer program
product, embodied in a computer-readable medium, including
computer-executable instructions, such as program code, executed by
computers in networked environments. A computer-readable medium may
include removable and non-removable storage devices including, but
not limited to, Read Only Memory (ROM), Random Access Memory (RAM),
compact discs (CDs), digital versatile discs (DVD), etc. Generally,
program modules may include routines, programs, objects,
components, data structures, etc. that performs particular tasks or
implement particular abstract data types. Computer-executable
instructions, associated data structures, and program modules
represent examples of program code for executing steps of the
methods disclosed herein. The particular sequence of such
executable instructions or associated data structures represents
examples of corresponding acts for implementing the functions
described in such steps or processes.
[0380] In the drawings and specification, there have been disclosed
exemplary embodiments. However, many variations and modifications
can be made to these embodiments. Accordingly, although specific
terms are employed, they are used in a generic and descriptive
sense only and not for purposes of limitation, the scope of the
embodiments being defined by the following claims.
[0381] It should also be emphasised that the steps of the methods
defined in the appended claims may, without departing from the
embodiments herein, be performed in another order than the order in
which they appear in the claims.
* * * * *